Horus Sanakht (Zanakht) relative position within the Third Dynasty is not yet sure. He was thought to be the successor of Djoser when no epigraphic trace of Horus Sekhemhet yet existed. Then for a long time the early-Lauer's opinion - Sanakht as foundator of the Third Dynasty - influenced and dominated the debates.
In recent years, this ruler's reign chronological order has been shifted again after Sekhemhet's reign. Archaeological finds in 1996 from Khasekhemwy tomb V at Umm el Qa'ab, Abydos, have led G. Dreyer to re-evaluate and prefer the direct succession Khasekhemui-Netjeryhet, thus causing Sanakht's reign to be moved after Sekhemhet's (or after Khaba). But the evidence from the necropolis of Zawiyet el Aryan, Beit Khallaf and Saqqara still show how hard it is to break the seemingly obvious continuity between Sanakht - Djoser (Beit Khallaf), Djoser - Sekhemhet (Saqqara Step Pyramid funerary Complex) and Sekhemhet - Khaba (similar 'comb-like' substructures of their pyramids).
To further make the question even more complex, the identification of the Horus-Sanakht with the king known as Nebka (cartouche name), is far from being an assured matter.

Now let's examinate in detail the possibilities one by one:
The hypothesis Sanakht after Sekhemhet is hardly possible because this would mean to separate Sanakht 's reign from Djoser's with c. 20 years and this is unacceptable for the Beit Khallaf mastabas architecture belong to close reigns; furthermore inserting a reign between Sekhemkhet and Khaba breaks the apparent continuity between these latter two sovereigns' funerary architectures: the Pyramid complex of Khaba, even in a minor scale, must be directly connected with the one of Sekhemhet (and the latter must have immediately followed Djoser's by its walls graffitos, the king lists and the cemetery choice evidence).
Sanakht after Khaba is still more unacceptable: for the same motivation implying the Bet Khallaf mastabas already explained; it's important to remember here that Khaba's ownership of the Zawiyet el Aryan southern unfinished pyramid (which the most of the scholars, including myself, continue to believe to be the most secure option) has never been demonstrated with full confidence.
Stylistically the Wadi Maghara graffitos seem to show few differences among Djoser, Sekhemhet and Sanakht reliefs.
A recent study by I. Incordino (in course of publication as PhD at IUO Napoli, 2007; also cf. below) based on the continuity of bidimensional royal portraiture canons / proportions and other variables, seems to reinforce the succession Khasekhemwy - Sanakht - Netjerykhet - Sekhemkhet - Qa-Hedjet.
I must admit that all the proofs mentioned above are strong but not conclusive, and each hypothesis could be contradicted or invalidated by new finds; also the possibility that Djoser buried his father Khasekhemwy is very strong, but this does not unequivocally exclude the possibility of a short interreign.

John Degreef suggested me (pers. comm.) that Sanakht could have directly followed Netjerykhet: also this possibility (supported by the seal impressions found in the Step Pyramid complex, North temple) becomes much more likely if we exclude a 19 years long reign for Sanakht (as the Turin Canon records, maybe owing to a confusion with the following reign's length). An ephemeral reign between Djoser and Sekhemkhet's reign would solve some if not all of the problems.
For a new hypothesis of this same succession (i.e. Netjerykhet - Sanakht - Sekhemkhet) proposed by J.P. Pätznick (2005), cf. the update below.

Now we can return to the 'proof' of the seal impressions of Netjeryhet found near Khasekhemwy's Abydos tomb (V) entrance; this has been interpreted as the definitive demonstration that the former king immediately followed the latter one, which is questionable too: seal impressions of the 2nd dyn. first king, Hotepsekhemui, have been found into Qa'a 's tomb, nonetheless we know that at least two kings (Sneferka and Bird), if ephemerally, did reign after Horus Qa'a and before the IInd Dynasty foundator .... (indeed the position of Sneferka and Bird is in turn puzzling and might be in the mid IInd dyn or, as for a possible third one, Horus Ba, even later).
I still think that Sanakht could have reigned before Netjeryhet, of whom he was probably a close relative; as we read in the page of Netjeryhet, Sanakht must have reigned only for a few years (alike Sekhemhet and Khaba).
As a matter of fact then, we have always been lead to think that Sanakht might have been a relative of Djoser: J.P. Lauer also advanced that they could have been brothers and that Djoser 'usurped' Sanakht's (M1) mastaba at Saqqara.
But if this would not be the case, and if Sanakht did belong instead to a different ruling family than Djoser's, another interpretation might be speculatively offered: presentiating at Khasekhemwy's burial, Djoser aimed to demonstrate that he was the natural and official successor, legitimating his right to reign beyond the fact that his relationship with Khasekhemwy was effective or not.
I mean that Djoser could have celebrated a "reburial" (and I don't want to be too extreme in supposing that the latest stages of tomb V at Umm el Qa'ab are a constructional tribute from a 'son' to his 'father') in order to ratify his position. There is no direct proof that Djoser could have been a kind of usurper (and it seem too odd to me even supposing such a theory), but the later sources' hesitation in the name of the foundator of the Third Dynasty fuels possible suspects that something like that might have occurred. And it seems that the 'Usurpation hypothesis' is the only way to explain some historical-artistical features that would appear otherwise incongruous. Yet this 'violent' appropriation must not be necessarily attributed to Djoser.
It's important to state, that the same conclusions could be drawn by hypothesizing, as it has been already done in the past, that the real act of force was accomplished by the more 'suspect' and shadowy figure of king Sanakht; therefore Djoser would belong to the dynastic line of Khasekhemwy, whereas Sanakht would continue the line of Peribsen or of the Memphite rulers of Mid IInd dynasty...
I am aware to be going too far with imagination; but let me consider a last element in favour of this theory which aims to stress the possibility that the mid-late Second Dynasty turbulences could have affected the Egyptian state up to the reign of Djoser.

I have expressed in other pages my doubts about the traditional way of interpreting the History of the Second Dynasty waving the flag of the Sethian revolution and/or eventually aiming to extract reliable historical data out of the analysis of myths (as K. Sethe did with large success).
Thus I am in a somewhat similar error in advancing the following hypothesis, which is based on a pure indication of display (a factor which should not be used or relied upon to build up conclusions), but let's consider it as an attempt, and as such with all the necessary cautions.
A possible sign of the presence of two rival dynastic lines might be found in the use of the cartouche name.
The earliest (doubtful) contemporary attestations are those of Sened (Nefersenedjra), Neferkasokar and Peribsen; later on Sanakht (as Nebka but only in IVth dyn. sources); Ninetjer, Weneg and, afterwards, Sekhemib Perenmaat (different from Peribsen) and Khasekhemwy, didn't use cartouche royal names (but Khasekhemwy did use the cartouche otherwise). The history would have handed down a (certainly too easy) peculiarity to help us in differentiating the two rival families struggling for the domain of the Egypt since the death of Ninetjer! Introducing the Second Dynasty we have already presented Wolfgang Helck's hypothesis of a voulountary split of the country in two reigns by Ninetjer (and the reasons for that hypothesis), as well as the links of the two 'courts' so created with the Upper and Lower Egypt.
In few words, Sanakht would be the scion of Peribsen's clan/family, Netjerykhet/Djoser that of (Sekhemib-Perenmaat's ? and) Khasekhemwy's. This would protract the fault in the vertex of Egyptian state up to the reign of Netjerykhet.
Khasekhemwy would have thus partially failed in reuniting the two lands, because a new member of the other stock would have arisen to the throne after his reign. Netjerykhet's has no such blatant elements in his names, epithets and inscriptions as instead Khasekhemwy had, a fact which lead us to believe in the reunification of the country by the latter king; but the interpretation of a will of Netjerykhet to unite the two opposites (be it on the level of the mythical Egyptian dualism or on a more real and historical basis) is clamorously recurrent in his funerary complex at Saqqara and in the same choice of a double burial in a unique place. [Please take these old ideas of mine above here cum grano salis, as they are extremely speculative].
This is where the scarcity of architectural and textual evidence has lead us to; only the K2 Mastaba at Bet Khallaf and (according to old opinions) some early structure in the Step Pyramid enclosure (the Mastaba 1 stage) can be doubtfully assigned to Sanakht (and quite nothing to Nebka); therfore he can hardly have been sitting on the throne of Egypt for more than a few years (2-6).
To conclude this argument we can summarize that only a few elements seem fairly trustable: Sanakht's reign can't be moved far from Djoser's one, and the equation with Nebka is to be proved. The relationship of both Khasekhemwy and Netjerykhet with Nimaathapi is a clue which tends to deny the presence of a reign in between these two (or at least a long one).
Mastaba K2 at Bet Khallaf, once thought to be related with Sanakht, is probably attributable to some high official or (his?) queen. Khasekhemwy's wife, Nimaathapi, has also been proposed for this tomb ownership, but her name appears only in K1 (with that of Netjerykhet and once also of Peribsen) (Vandier -Manuel I , 870 ; Reisner - Develop. ; Lauer - Pyr. Degr.); various inscriptions and seal impressions of Sanakht have been found in K1 (Kahl et al. 1995 p.140-151, all very fragmentary).
In the main (the southern one) of the two burials within this tomb, bones were found belonging to a tall man (almost 1,90 m) and Manetho cites that one of the last king of the second dynasty (Sesochris) was more than 3 cubits tall... The wooden sarcophagus had been eaten by ants (John Garstang op.cit. p. 11-14; Nabil Swelim Some Problems, 1983, 95).
No trace remained of the name of the deceased buried in the northern sector of this double tomb (almost certainly the owner's wife).
The fig. below can give a good idea of the brick monument excavated by Garstang; the superstructure is smaller than K1 being m. 65 x 23,5 (K1 is 85,5 x 46m); the double substructure appears of older type than the more evoluted in K1; but the author (Mahasna and Bet Khallaf, 1903 p. 11) stigmatized the similarity of its superstructure with the Step Pyramid of Netjerykhet: K2 was infact built on a low bench-like step and its own superstructure seemed to have been a stepped one (or at least with a steps- core). Two parallel walls perpendicular to the south side of the tomb were possibly ancient ramps.
Bet Khallaf K2 (after John Garstang  op.cit. pl. 18, description p. 11-14)
According to Petrie (A History I, 7th edit., p. 29-30) Sanakht was identical with both Nebka and Nebkara; Barta has recently reproposed the same opinion. R.Weill (II et III Dynasties) equated Sanakht with NEFERKA.
As I've resumed above, in these years it has been again considered (Swelim, Dreyer, Kahl) the hypothesis that Sanakht might be placed chronologically after Djoser and Sekhemhet.
Some traces do indicate that Nebka would have used a cartouche (seshen); but during the rest of the Third Dynasty the use of Horus names (in the Serekh) continued to prevail, until the definitive change of importance happened under Huni, Snofru and Khufu for whom the (Nswt Bity) cartouche names are the most common royal name indicators. As I ve mentioned above, the earliest appearances of cartouche-encircled royal names are dated to the preceeding dynasty as it is shown by the examples of Nefer-Senedj-Ra, Neferkaseker and by an unpublished sealing of PERIBSEN at the Civiche Raccolte in Milan (RAN 997 02 01) (this piece is recently appeared on the Ravenna 1998 exhibition catalog A.M. Donadoni Roveri, F. Tiradritti (eds.), 'Kemet. Alle sorgenti del Tempo', 252; Nabil Swelim -pers. comm. 2001- has shown me his skeptisism about the autenticity or archaic datation for this sealing).
The oldest evidences for the name NEBKA are the inscriptions of the Akhetaa mastaba (Saqqara Q 3345-3346) and others from Abusir (in cartouche) now in Berlin and Leipzig Museums (Kahl et al. 1995 p.202-5(Nebka), 140-51(Sanakht)).
All the attestations of his name are in N. Swelim (op. cit. p.189).
Drawing of a seal impression found in Saqqara 2322 by J.E. Quibell ('Archaic Mastabas' p. 34)
There is also a faint impression on clay jar-stoppers which was found by J.E. Quibell (Archaic Mastabas 1923 p.34) in the Saqqara tomb S2322 (c. 40 m. east of Ruaben S2302); but this could have no relation with a royal name, and the tomb is clearly of middle 2nd dynasty, not later (cfr. tomb and stone vessels found in it in Quibell op.cit. pl. 1, 20, 21, 30).
Nabil Swelim (in 'The Dry moat of the Netjertkhet complex', in Baines et al. ed., Pyramid Studies and other essays presented to I.E.S. Edwards, 1988 p. 12-22 esp. p.15) points the attention to a newly found tomb south of Djoser's complex: the owner' s name is NiankhNebka (Nebka in the cartouche appears twice in this tomb); this has been found by Said el Fiki east of the tomb of Irukaptah (south of Unas causeway) and it could indicate the presence of a cult of Nebka before the Vth dynasty.
It can be paired with the name of another tomb owner, NiankhBA (buried circa 50m NW of this tomb), also formed with a (possibly) Third Dynasty king's name (for 3rd-early 4th dyn mudbrick mastabas N of Unas causeway cf. Ghaly, MDAIK 50).

By this resumée we have seen that it's still today object of debate the belongings of the names Nebka / Sanakht to an individual king, although most of the Egyptologists still accept it on the basis of a rather weak proof: Kurt Sethe read [NEB] KA onto a seal impression from Bet Khallaf (where the two names look coupled cfr.Cambridge Anc. Hist. vol. I pt.2 pag 157 and Drioton-Vandier -CLIO- p.200) with the only .... KA surely readable in the cartouche name (Garstang, Mahasna and Bet Khallaf, pl. XIX,7; see drawing below).
I am inclined to think (as Helck 'Thinitenzeit' p. 107) that Nebka and Sanakht are two separate kings, but it is hard even to find reasons or proofs for placing the former after the latter (see Helck in Z.A.S. 106,1979 p. 130).
After all even if the cartouche of the seal impression was that of a king, it could be related to some official (Kherep or Hm) employed in the granaries of some previous king's domain or being a place name (as in Peribsen's I.A.F. 750, Nwbty).
The cartouche and the serekh, although close to each other, are nor one after another in the same line, and indeed the two columns face each other.
I want to add a further possibility to the already proposed interpretations of the last sign in the cartouche as Ka or Ra: it could be the prow of the boat determinative known in some inscriptions of Peribsen's domain (Ity-Wiaw) (see i.e. Kaplony I.A.F. III n.283, 286) written in the cartouche instead of within the usual crenellated oval of the archaic kings' funerary domains.
Hem- (or Kherep- ?) Shenwt [...Ka?]
Apart from the mentioned fragments of a tomb in Abusir naming a priest in the funerary temple of NEBKA (Leps. Denk. II,39), there is, not far from there, in the funerary temple of Niuserra, the indication of a property of NEBKA (Borchardt 'Grab. N.' 79).

References on scarabs of NEBKA are in Petrie (A History of Egypt I, pp. 29,30 - 7 ed.): Sayce, Fraser, Petrie.
On the scarabs the name is closed in a cartouche and the hands of the hieroglyph 'ka' are of ovoidal shape; these indicate their late period origin, although some possibly late Old Kingdom (?) examples already show this feature (cfr. parallels in Kaplony 1963,1981, see Neferkaseker, Nebkara).

Mr J. Degreef has shared with me (e-mail communications) his idea that the name Nebka would be the birth-name (or part of the royal titlulary) of Khasekhemwy. This fact would solve some problems and create others. And this theory would have an higher probability to reflect the truth whether the earliest attestations of Nebka were of Middle Kingdom or later date, but we ve shown that this is not the case. Anyhow the equation Nebka = Khasekhemwy, although never attested in contemporary and later documents, has one great and unneglectable merit: it is the only way to explain the outstanding echo of this royal name Nebka; I mean that there's no other king in late Second Dynasty up to the late Third (except for Djoser which can be excluded) for whom such a 'fame' would be justified like it'd be for Khasekhemwy. This hypothesis must be seriously considered.
However it can be also hypothesised that Nebka(-ra) was the name of a scarcely known (if not completely forgotten) Horus king whose archaeological records have been completely obliterated by time.

I can't omit that it has been also thought that no Nebka might have ever existed in the Third Dynasty, but, as shown by the Akhetaa reliefs, this would have been a IVth dynasty king or prince of the still partly undetermined period between Khaefra and Menkaura (cfr. the Wadi Hammamat graffito naming Bauefra and Djedefhor).
The fact that traces of this king's name appear already in the IVth and Vth dynasty, prevents from thinking that a kind of later conflation of a semi-mythical hero merging more kings' figures like the legendary Sesostris or, possibly, the same Menes did occur in this case.

Another alternative is that Nebka would be the personal name of Horus Qa-Hedjet (this has been proposed for Huni/Nisut-Hw too).

Horus Zanakht : 2 reliefs from Wadi Maghara, Sinai (ancient Mefkat)
The Horus name SANAKHT is among the ones found in the Sinai near Wadi Maghara; it's useful to compare these reliefs to try to establish a stylistical relative sequence of Sanakht as predecessor or follower of Djoser (see the apparently more archaic style of the reliefs reproduced in the figure above -Smith H.S.P.O.K. pl.30c- than Netjerykhet and Sekhemkhet's; cf. I. Incordino, op. cit.).
The inscriptions reaffirm the control of the king over the Sinai territories or, at least, the exploitation of the turquoise mines (the last part of the toponym [M]efkat can be read on the right side of the BM relief, in the fig. above, bottom-right corner).

Even if, as it was said, the name Sanakht appears at Bet Khallaf, no trace has been found here of a mastaba that might be surely have been his own; it has been (not merely speculatively) suggested, that the first building- phase (Mastaba I) of Djoser' s pyramid at Saqqara was a Sanakht 's effort.
Alternatively it was proposed as his burial place the pit-gallery #3 under the east side of the same pyramid, where J.P. Lauer (in BIFAO 79, 368-9) thought that Djoser would transfer Sanakht's body.

In 1927 a rough vessels deposit in the north east corner of Djoser's funerary temple, yielded two seal-impressions of Sanakht (C.M. Firth - J.E. Quibell, 'The Step Pyramid', 1935, 141, fig. 18; P. Kaplony, IAF I, 170). On one of them, the royal serekh appears amidst titles of the Hrj-Hb [Hm-nTr] Neith and part of the standing figure of the goddess holding a was scepter in the left hand (cf. Kahl et al., Die Inschriften der 3. Dynastie, 1995, 150-151).
This is a very important evidence, although numerically scanty in itself. Furthermore, although found in situ, Quibell expressly wrote that they came from "a place which was accessible after Zoser's funeral, and thus give no indication of whether Sanakht cam before or after Zoser" (Step Pyramid, 141).

A Seal impression of Sanakht has been found in the '80ies by the German archaeologists working at Elephantine (Kaiser, MDAIK 38, 308, fig.15, pl. 65b): it mentions the (unnamed) Lower Egyptian sealer of the Per-Nswt of Horus Sanakht.

[Update Aug/2007]: The publication of Third Dynasty seals and sealings from Elephantine (Jean Pierre Pätznick, Die Siegelabrollungen und Rollsiegel der Stadt Elephantine im 3. Jahrtausend v. Chr., Oxford, 2005) has improved our knownledge of the early administration of the State, although it was clear since long before that these developments were taking place already in the predynastic and more intensively during the Early Dynastic period.
A seal impression with Sekhemkhet's Nebty name (Htp-Ren...-Nebty) has reopened the question of the belongings of the similar royal title, found on the Saqqara linens plaque from Sekhemkhet's Pyramid. Pätznick (op. cit., p. 76-79) proposes that the Nebty Djeserty Ankh might have been the Nebty name of the king who really started the building program of the so called 'Sekhemkhet Pyramid complex'. This king was likely Horus Sanakht, whose reign -for a number of reasons I have illustrated above- is impossible to detach from Netjerykhet' one (also cf. Pätznick, op. cit., 78 and note 821).
Nonetheless, in recent reconstructions (cf. Kahl et al., op. cit., 1995; Baud, Djéser et la IIIe Dynastie, 2002), Sanakht's reign had been shifted towards the mid(-late) IIIrd Dynasty, mainly as a consequence of the "ascertained" direct succession of Khasekhemwy and Netjerykhet (based on G. Dreyer's publication of seal impression of the latter king in Khasekhemwy's tomb V at Abydos- which is in my opinion a good clue that Djoser wanted to emphasize the direct line of succession with Khasekhemwy, but not a certain proof that a direct succession really occurred: cf. the case of Horus Qa'a and Hotepsekhemwy).
On the other hand Pätznick proposes that Horus Sanakht / Nebty Djeserty Ankh, shortly reigned after Netjerykhet and before Sekhemkhet. This latter king's unfinished pyramid complex, would be indeed Horus Sanakht's one (possibly Sekhemkhet appropriated it when Sanakht prematurely died, but in turn he himself must have been dead after few years of reign. Alternatively Sekhemkhet's complex would be still under the sands of the Memphite cemeteries).
Further indications of the close relationship between Djoser and Sanakht are considered the sealings of these two rulers from Bet Khallaf mastaba K2 and the strict proximity of these kings' reliefs in the Wadi Maghara, Sinai (whereas Sekhemkhet's ones were carved much farther uphill).
Another reconstruction, mainly based on Bet Khallaf and Wadi Maghara (plus SPC Saqqara) documents (archaeological, epigraphical and stylistical analysis) has been offered by Ilaria Incordino (Istituto Universitario Orientale, Napoli) who proposes the classic succession Sanakht - Netjerykhet - Sekhemkhet, but on new grounds.
At present, the identification of the kings on Palermo Stone line V as the last ruler of Second Dynasty (Khasekhemwy) and the builder of the Step Pyramid complex (itself or part thereof named QbH-NTrw on the Annals as on the Turin reliefs from Heliopolis) early at the head of what was then to be called the "Thrid Dynasty", makes the succession Djoser - Sanakht - Sekhemkhet more plausible than the other ones, though not yet out of any doubts.
[End of Update]

A. Dodson (KMT 9:2,1998) has reproposed Swelim's theory that one of the two Abu Rawash mudbrick structures might be the tomb of Nebka (if indeed he is the first king of the dynasty); it's a "mudbrick enclosure 330 x 170 m with a 20 meters central square massif of the same material, located north of the modern village of Abu Roash, known as El Dair. It has been badly damaged by drainage work since first being discovered in 1902, and now may be beyond saving. However, the plan seems to closely resemble royal funerary monuments of the late Second early Third dynasties, while pottery from the site has been dated to the latter period". (A. Dodson, KMT 9:2, 1998, 30)
Howard Vyse reported in 1837 mudbrick structures in the plain north of Abu Rawash; the site of El Deir was excavated in 1902 by Palanque (BIFAO 2, 1902, 163-70), but only in 1931 the eastern side of the enclosure wall and the mudbrick massif were found by Macramallah (ASAE 32, 1932, 161-73) who attributed -with some doubts- that 'fortress' to the Middle Kingdom (description and plan have been included in the appendix to N. Swelim's 'The Mudbrick Pyramid at Abu Rawash' 1987 p. 91-95).
Nabil Swelim (S.P., 1983, 36-9), the first scholar to link Sanakht with Abw Rawash, gives more details and a plan of the enclosure. No entrance has been discovered (although only the southern part of the eastern wall and c. 50 meters of the eastern part of the southern wall are preserved) but two smaller walls perpendicular to the main one, have been interpreted as a possible structure which could be a ramp for the entrance in this complex (they' re placed outside the southern part of the eastern wall, about the same place of the other enclosures' entrances).
[ El Dair plain sketch - N. Swelim, The Mudbrick Pyramid at Abu Rawash, 1987, 92 ].

No official of Sanakht is known with certainty: Nedjemankh could have begun his career under this king; Menka, the noble, administrator and visir (Cambridege Anc. History vol. I pt. 2, 1971) could have instead ended his under Sanakht, but he more probably lived by the end of the second dynasty: he is actually named on some inscriptions of Djoser complex stone vessels, and these are all dated to the first two diyasties. (The 'visir' title -Thaty- appears, before than Menka, only on the Narmer Palette whereon it is really doubtful whether it stands for a public office or not). The writing 'Men-ka' appears also on one of the two reliefs from Gebelein (the one in Cairo, W.S. Smith H.E.S.P.O.K. pl. 30,d) depicting perhaps a (Khasekhemwy's ?) foundation ceremony, above a female offering bearer (but the name could be the continuation of a fragmentary inscription on the right, or indeed not being a person-name at all).
Other inscriptions, from Saqqara (with no royal name on them), bear the names of Htp Hpn and of Khnum-ii-n-i, maybe two individuals who lived in that period (cfr. R. Weill in RdE 3, 125-6) but more probably these are earlier (Ninetjer-Khasekhemwy).

The mentioned tomb Bet Khallaf K2 (with two ramps and two separate internal areas) contained fragments of seal impressions with Sanakht name and some titles (Overseer of the granaries), 2 officials' names: Inpuhotep and Sekhem Mery Maat (Petrie, A History I p.30 7th edition).
The cited Akhetaa, a late III rd dyn.- early Fourth dynasty priest, is said to have served in the funerary temple of Nebka (Helck in Z.A.S. 106p.129) as some of his Saqqara funerary chapel inscriptions show (cfr. above; Helck 'Thinitenzeit' 1987 p. 244 ff - AaAkhty -).
Nebka might have been either the Nswt bity name of Horus Sanakht and it must not be necessarily dissociated from "NEBKARA" (a name found in NK king-lists and on a few more late inscriptions).
It's worth to repeat that a NEB-KA transcription was first given to the coursive writings on blocks from the cited Zawyiet el Aryan unfunished pyramid (named: Nebka is a star) (cf. ASAE 7, 257-86 ; RdE 14, 21-36); but, as we said, not even completely convincing is their attribution to the phantomatic NEBKARA \ NEFERKARA (late 3 rd dyn.) because these structures are dated to later OK after Lauer's studies (cfr.Lauer, in RdE 14; Cerny, in MDAIK 16; cfr supra and Nebkara's page).
We can't leave out the hypothesis of a reusal by un unknown king of stone blocks marked for Nebka's burial; it is not so strange, if this was the case, that the inscriptions weren't erased (see for a recent recollocation to the III rd dyn. Dodson, DE 3, 1985, 21-23; id., ZAS 108, 1981, 171). N. Swelim rejects Lauer's IVth dynasty date for the Zawiyet el Aryan great trench / unfinished pyramid.

In the Royal Canon of Turin NEBKA (col. III,4) preceeds Djoser and is told to have reigned for 19 years.
Until recently, the Petrie Museum Annals fragment recto (cfr. Helck cit. p.166) and the Palermo Stone recto (V,1-7) were considered to mention, respectively, years 4-7 and the last seven years (v .Barta op. cit.) of his reign*; in a slight discordance with the Turin Papyrus, the Palermo Stone annals seem to give only 17 years, 2 months, 23 days of reign to Nebka*. Both seem to be too long periods for such a poorly attested reign, expecially in the light of the equal length of 19 years transmitted to us for the reign of the notorious successor.
The most recent reconstructions seem to acknowledge that the end of the reign on Palermo Stone V wasn't Nebka's one but rather that of king Khasekhemwy, followed by the early reign of Djoser (M. Baud, Archéo-Nil 9, 1999; T. Wilkinson, Royal Annals..., 2000; M. Baud, Djéser et la IIIe dynastie, 2002).
*[Note: these are scholars' reconstructions: the most important are those of Kaiser, Helck and Barta; they 've hypothesized the belongings of the Annals'(recto) reigns in relation with the only readable royal name (Ninether on the row V and Snofru in VI) and relatively to the supposed width of the entire wall on which they were carved); but it seems certain that the two reigns in Palermo Stone line 5 are those of Khasekhemwy and Djoser].

Manetho reported 28 years for the III rd dyn. founder Necherothes(or Necherophes) a name that sounds highly similar to the Horus name of Djoser, Nethetyhet, that he spells Tosorthros; but Manetho never mentions names deriving from the Horus name and, in all cases, the hint to Imuthes (Imhotep) in connection with the second king of the dynasty III, takes any doubt away. Also Manetho placed NEBKA at the end of the II nd dynasty, possibly in order to exhalt the position of Djoser as a foundator (the Royal Canon of Turin has it in red ink probably because Djoser was at the top of a column in the original papyrus from which the Turin document was copied).
The opposite device, Nebka's postponing (but it could instead also reflect the true historical sequence), seems to have been adopted (for the same purpose) in the famous tales of the Westcar Papyrus: after a prince of Khufu (no name remains but he was possibly Djedefra or Kawab) had told a short episode happened at the time of Djoser, Khefren in turn refers a prodigy of the age of the 'father' (ancestor) of Khufu, NEBKA; a chief ritualist of Nebka, Ubainer, punished his wife's lover by throwing a wax figurine into the water where the object became a crocodile which devoured the guilty man; Ubainer's unfaithful wife was burnt by Nebka, her ashes spread in the river waters (Pap. Berlin 3033). (Cfr. also Wildung 'Die Rolle ...' 1969, 54-57).
M. Baud (Djéser et la IIIe dynastie, 2002, 60f., 284) cites an article by Mathieu on this tale, in which a negative image of Nebka seems to emerge; Baud also stresses the fact that the tale seems to reflect the real historical succession of kings because the first three tales of the papyrus relate to Djoser, Nebka and Snofru respectively (this agrees with the presently preferred order which places Nebka's reign in the later half of the dynasty).

Wolfgang Helck, who as we have told, denied the identity Nebka-Sanakht, also refused the identification of Sanakht with a mysterious Horus ZA whose name has been found on stone vessels inscription from the Djoser's complex east galleries naming "the Ka-house of Horus Za". Za could be the Horus name of Wng (cfr. Kaplony in 'The Nile Delta in transition' p. 28; Helck 'Thinitenzeit' p. 107-8; Helck Z.A.S. 106 p. 128,130).
Manetho briefly tells of a lybian rebellion happened under Nebka, but we know no further event for this period. This information can be an echo of the military raids documented for Khasekhemwy (whose birth name might have been Nebka in Degreef hypothesis quoted above).
Certainly the evolution in the administration of a very wide territory is already in progress as the traces found on the southern frontier outpost of Elephantine (and the dignitaries' titles proliferation) demonstrate. (For Khasekhemwy-Nebka-Djoser possible family relationship and Nebka different from Sanakht see Helck, 'Thinitenzeit', 1987, 107-9).

Kaplony (RAR I, 1977, 146-155; cfr. table in my Third dyn. page) proposed to identify Horus Za with njswt-bity Wr-Za-Khnwm (id., IAF I, 380, 468, 611) as Djoser's father and predecessor (interregnum of 2 years and 23 days); Horus Nekhet-za (Sanakht) would be for Kaplony Hor Tehenwy Nwb (IAF III, n. 806) and njswt-bity Nebka(-Ra) the follower of Sekhemkhet and predecessor of Khaba.

For Nebka(-Ra) as the possible cartouche name of Qa Hedjet see above.

[For Sanakht on the WWW see also Mercier's page]
All the inscriptions are collected in J. Kahl - N. Kloth - U. Zimmermann 'Die Inschriften der 3. Dynastie' (1995) p. 139-151 (Sanakht) and p. 202-205 (Nebka).
For the direct succession Khasekhemwy - Djoser, and Nebka to be placed in the second half of the IIIrd dynasty cf. G. Dreyer, Der Erste König der 3. Dynastie, in: Guksh- Polz (eds.), Stationen... R. Stadelmann gewidmet, 1998, 31-34; Cf. also M. Baud, Djéser et la IIIe dynastie, 2002.
- A photographic reconstruction of Bet Khallaf, Mastaba K1 (by Ottar Vendel, 2006)

Index:   Historical Data
The Antecedents
The Third Dynasty
Khaba (Sedjes)
Qa Hedjet