Boris Avrukh (1.d4 Volume Two, Glasgow 2010) gives 1.d4 Nc6 2.d5 Ne5 3.e4 e6 4.f4 Ng6 5.dxe6 fxe6 6.Nf3 6...Bc5?! 7.Nc3 Nh6 8.f5 Nh4 9.Ng5 ("!N"), which is indeed good for White. But he ignores 6...b6, 6...Bb4+ and 6...d5.

[quote author=62616B6D0C0 link=1271505369/87#87 date=1273915374]The suggestion of 9 …Nfd7!? instead of Herzog’s 9 …a6 is just what I’d thought earlier might be Black’s best (#74, 69)![/quote]
Michael, I've overlooked that you had already recommended ...Nfd7 - my apologies. It seems reliable enough for an otb game or two. W. - Herzog isn't much worse, and there are perhaps 30-50 other good alternatives for Black along the way. So for the rare 2...Nb8 game, there is no lack of options.

1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 0-0 6.h3 Nc6 7.d5 Nb8 8.Bd3 "+=" Nunn. 8...c6 (not too bad: 8...e5 9.Be3 Nh5 Bystryakova - Gaprindashvili, St. Petersburg 2007) 9.0-0. The += is probably fair. But the flexible 9...Nfd7(!) looks good, followed by Na6-c5 and an eventual a5.

[quote author=282B2127460 link=1271505369/82#82 date=1273873700]Obviously I want to think this is so! But I am confused! How early do you feel Black can/should play ...Bg4 if allowed (or to put the same thing another way, how early could White profitably prevent it with h3)? In one way it seems logical to think Black should play ...Bg4 immediately in reply to e4, but I'm often worried that if White hasn't developed his KB, h3 might be a strong reply (and also maybe Qb3). So, for example, in the next game that Berdichevsky gives -- Ovsejevitsch-Istratescu, which went 1 d4 Nc6 2 Nf3 d6 3 d5 Nb8 4 c4 g6 5 Nc3 Bg7 6 e4 Nf6 7 Be2 0-0 8 0-0 Bg4! -- should Black have played 6 ...Bg4, and given that he played 6 ...Nf6 instead, why wasn't 7 h3 and 8 Bd3 strong?[/quote]
I am confused, too. While I only claim that 2...Nb8 is reasonable, certainly better than +/- or "disregarded" (your word in post #64), you are worrying about such subtleties. After 1.d4 Nc6 2.d5 Nb8 3.c4 d6 4.Nc3 g6 5.Nf3 Nf6 6.e4 (reaching Wirthensohn - Herzog), Black now has 6...Bg4, as in e.g. Grünfeld - Alekhine, Margate 1923 (=, 32). 
If White combines h3 & Be2, we enter a KI side-line (Bogolyubov - Yates; Balashov - Kuzmin etc.) where Black's small "sin" to have played Nc6 before e5 isn't too tragic because of the slower h2-h3. 
It may be a concession to play Bg4 early, but on the other side White has made a concession himself (d4-d5) which saves Black some work (e.g. Bg4, Nfd7, Nc6 puts d4 under pressure, hoping for d4-d5).
Since I am not the greatest KI expert, you should rather consult a book. The problems seem relatively minor to me. 

Obviously I want to think this is so! But I am confused! How early do you feel Black can/should play ...Bg4 if allowed (or to put the same thing another way, how early could White profitably prevent it with h3)? In one way it seems logical to think Black should play ...Bg4 immediately in reply to e4, but I'm often worried that if White hasn't developed his KB, h3 might be a strong reply (and also maybe Qb3). So, for example, in the next game that Berdichevsky gives -- Ovsejevitsch-Istratescu, which went 1 d4 Nc6 2 Nf3 d6 3 d5 Nb8 4 c4 g6 5 Nc3 Bg7 6 e4 Nf6 7 Be2 0-0 8 0-0 Bg4! -- should Black have played 6 ...Bg4, and given that he played 6 ...Nf6 instead, why wasn't 7 h3 and 8 Bd3 strong?

I think we might be talking slightly at cross-purposes Stefan -- sorry if I created some confusion! I'm interested in this discussion/thread essentially for the very simple reason that I'm interested in 1 d4 Nc6!? full stop, not because I'm looking to create KID/Pirc-style positions with ...Nb8 wherever possible. (And much less because I'm wanting you or anyone to list all such possible transpositions! -- a fascinating project that would certainly be for another thread, if not another lifetime ...) Indeed I don't think it's a good idea to 'fixate' on particular setups like that even though we all of course have our favourites. Much better to keep flexible! -- and we chessplayers have to be undogmatic and open-minded, do we not? 

That, I guess, is why I'm interested in both Black second moves after 2 d5; and I cited the W.--H. game (here and in the other thread) just because I thought -- rightly or wrongly! -- that the d5/e4/c4/Bd3 setup posed the biggest challenge to 2 d5 Nb8!?, and this game is cited in Berdichevsky's book. (I also had a strong 'vested interest' in this setup as it can arise from my favourite Nimzowitsch Defence [with 2 Nf3 d6], and indeed other openings.)

I haven't explored 1 d4 Nc6 2 d5 Nb8 much yet, but this far it seems to me that what's fascinating is not just the transpositions that are possible from this position, but also the range of setups closely analogous to other more mainstream openings (near-transpositions, if you like) that the players can, with their various third moves, start to construct between them.

Nice one! -- as often, I was a bit too hasty. Incidentally I noticed this game before out of the corner of my eye, but seeing the players' ages and ...Bd6 failed to take it seriously -- big mistake! In a way this line makes the whole thing quite attractive, since a lot of Whites (at least at my level!) might go after the Bishop and so give black a decent Tango-style position.

Will take a look at 3 Nf3 f5!? (I guess the challenge here is to avoid being a tempo down on a Leningrad or 2 Nf3/3 d5 Dutch ...). [b]Edit:[/b] maybe 3 Nf3 [u]Nf6[/u] 4 c4 e6 is worth a look (5 Nc3 Bb4 (or Bc5))? 3 c4 e5!? 4 Nf3 and I guess 4 ...e4 and 4 ...Bb4 both make some sense?