mangler wrote on 11/12/07 at 21:59:45:
For those who are not so adventurous, please note that 1.c4 Nf6 2. Nc3 e6 3. e4 e5 can also be met by 4.Nf3, and if 4...Nc6 (what else?), white is a tempo up on the 4.e4 variation of the 4 knights English. Perhaps not so dangerous, but I would think white should get an edge with the extra move.
That's what I thought at first, but one must wonder. It seems like the sort of position where White would almost prefer it to be Black's move. For instance on 5. g3 Bc5, 6. Nxe5 is not on. 5. Be2 Bb4 produces a position where it seems White would rather be playing g3 and Bg2. 5. d4 seems critical, but in comparison to 1. c4 e5 2. Nc3 Nf6 3. Nf3 Nc6 4. d4, having the pawn on e4 already doesn't look like an unalloyed good (target for ...Bb4; even 5...ed 6. Nxd4 Nxe4 [like a line in the Scotch] comes to mind but is bad). Or comparing 5. d4 Bb4 or 5. d4 ed 6. Nxd4 Bb4 to their Scotch counterparts, might not the c4-pawn interfere with some 4th-rank stuff by White's queen?
5. d3 may offer an edge in the case of the tempo-up normal line which arises after 5...Bb4 6. g3, but Black can play 5...Bc5 (then 6. Nxe5 and d4 loses back the tempo and transposes to a normal line which is supposed to be about equal). 5. a3 is a thought (à la the 4. a3 Four Knights English, or the Mengarini thing in the Vienna), but is that likely to lead to any advantage after, for example, 5...g6? I suppose one plausible line is 6. d4 ed 7. Nxd4 Bg7 (7...Nxe4 bad) 8. Be3 0-0 9. Be2 Re8 10. f3 d6, producing a KID which is reckoned to be slightly better for White without the extra move a3, but the inclusion of that move looks like it has "negative usefulness" for White.