White 29
 

[QUOTE=cheesehead;373665]- -

But there is one line where we don't have a forced piece-win [I]as far as I've seen [U]so far (but I'm not finished with the analysis)[/U][/I]: [B][B][B][B][B]28 ... Ndf5 [/B]29 g4 Nh4 [/B]30 Nd6+[/B] Kd8 31 Nxc8[/B] Kxc8.[/B] (Actually, I'm posting this before completing my analysis, so I/we may yet find a piece-win in this line!)

If [B] 32 Nxe6 [/B](threatening 33 Nxg7)[B].[/B] Now
If [B]32 ... Bf6 33 ???????[/B]
If [B]32 ... ??????[/B]

If [B]32 Rxe6 [/B](threatening 33 Rxe7)[B] Rb1+ 33 Kf2
[/B]
If [B]33 ... Rb2 34 Bb7+
[/B]If [B]34 ... Rxb7 35 Nxb7 Kxb7 36 Rxe7+[/B] and [B]37 Rxg7
[/B]If [B][B]34 ...[/B] ???????[/B]

If [B]33 ... ???????[/B]

If [B]32 ?????[/B][/QUOTE]Just some thoughts, not rigorous analysis, about the position after [B][B][B][B][B]28 ... Ndf5 [/B]29 g4 Nh4 [/B]30 Nd6+[/B] Kd8 31 Nxc8[/B] Kxc8[/B]:

a) [I]We still have to keep in mind the Bd4+ fork threat _and_ the Nf3+ fork threat[/I] !

It may be desirable to get our c-pawn off the long diagonal so that our B/d2 doesn't have to guard it, but ...
32 c4 [U]would actually lose a piece[/U] to
32 ...Bd4+ 33 Be3 Bxe3+ 34 Rxe3 Rb1+ 35 Kf2 Rb2+ 36 Re2 (or 36 K-moves Nxg2 or Rxg2) Rxe2+ 37 Kxe2 Nxg2.

b) The N/h4 is not necessarily stranded there.
Black could advance ... g5 to both protect the N/h4 and give it a potential retreat at g6.
We could try 32 g5, hoping for 32 ... hxg5 33 Bxg5, but that just re-opens f5 for one of Black's knights (and un-guards our c-pawn).

After [B][B][B][B][B]28 ... Ndf5 [/B]29 g4 Nh4[/B][/B][/B][/B],
what does
[B][B][B]30 Nd6+[/B] Kd8 31 Nxc8[/B] Kxc8[/B] get us?
Removes the defender of the e6-pawn, that's what. But it liquidates Black's cramped light-square bishop at the expense of our well-posted N/c4.
[I]Maybe [B]30 Nxa5[/B] would be better.
[/I]That would allow [B]30 ... e5[/B], letting their B/c8 menace our g4-pawn. [I]But it also transforms our a-pawn into a threat![/I] E.g., [B]31 h3 Ng6 32 Nc4[/B] and Black cannot easily maneuver to stop a5-a6-a7-a8.

Considerations like that last one may well prompt the Gekkota to play [B]28 ... Ndc6[/B]. <== That's what I expect.

While I was going over some sequences, I found that after [B]28 ... Ndc6 29 Nd6+ Kd8 30 Nxc8 Kxc8[/B],
[B]31 Bxc6 Nxc6[/B] removes an impediment to some of our attacking lines. E.g., [speculative example]
32 Rxe6 Rb1+ 33 Kf2 Nd8 34 Rxg6 Be5 35 Rg8 Kc7 36 Re8 Bd6 37 Ne6+ Nxe6 38 Rxe6 Rb6 39 Bf4 forcing a swap-down to a winning king-and-pawn endgame.

[QUOTE=cheesehead;373832]While I was going over some sequences, I found that after [B]28 ... Ndc6 29 Nd6+ Kd8 30 Nxc8 Kxc8[/B][/QUOTE], if we capture the N/c6 (so as to cause the N/e7 to move, unguarding g6)
[quote][B]31 Bxc6 Nxc6[/B][/quote] before taking the e-pawn, that
[quote]removes an impediment to some of our attacking lines. E.g., [speculative example]
32 Rxe6 Rb1+ 33 Kf2 Nd8 34 Rxg6 Be5 35 Rg8 Kc7 36 Re8 Bd6 37 Ne6+ Nxe6 38 Rxe6 Rb6 39 Bf4 forcing a swap-down to a winning king-and-pawn endgame[/quote], but a better fight for Black would be
32 ... Ne5 (threatening Nf3+ forking the K and B) 33 Kg2 Rb2 34 Ne4 h5 (not Nc4 35 Rc6+) 35 Kf1 Nf3 36 Bf4 Rxh2 37 Re7 Ra2 38 Rxg7 Nh2+ 39 Ke1 Nf3+ 40 Kd1 Ng1 41 Nc5 Ra1+ 42 Kc2 Kd8 (avoiding 43 Rg8++) 43 Rxg6 etc.

I think that the former path we discussed, 28..Ndc6 29 Nxe6 is a better reply here. Direct attack, more aggressive, black can only beat the horse or move Kf7 to protect the bishop (moving the bishop is bad). Bxe6 Rxe6 and they have to lose precious moves to save that horse. There is a bit complicate by the Rb1 attack, and other little tassels they can do, but the main line, we get a good pawn advantage and better position. If Nd8, then Ra6 is viable and we get two pawns...

Still looking into it, but the best would be to wait for their move. I believe that 28..Nef5 will follow, and not 28..Ndc6 :razz:

Less than [strike]eight[/strike] seven hours until their deadline.

[QUOTE=LaurV;373863]I believe that 28..Nef5 will follow, and not 28..Ndc6 :razz:[/QUOTE]

Hey! I just only now looked closely enough at what you wrote: 28..N[U][B]e[/B][/U]f5

[B]28 ... Nef5[/B]

[B]29 g4[/B]

If [B]29 ... Nh4 [/B](not ... Nc6 30 Bxc6+)[B] 30 cxd4[/B] [B]Bxd4+ 31 Be3[/B]
[speculation] 31 ... Rb4 32 Nd6+ Kd8 33 Bxd4.
If 33 ... Rxd4 34 Nxc8
If 34 ... Rd2 (threatening to take the B/g2) 35 Bb7

[QUOTE=cheesehead;374057]Hey! I just only now looked closely enough at what you wrote: 28..N[U][B]e[/B][/U]f5[/QUOTE]
:sad: Actually, I also only now looked (due to your post) and have seen what [B][U]I[/U][/B] wrote... It was a mistake, supposed to be Ndf5, as you correctly assumed from the start. Nef5 was discussed in the former topic ([URL="http://www.mersenneforum.org/showpost.php?p=373641&postcount=13"]move #28 post #13[/URL]) and we decided that is bad for black. Then you said (in the following post) Ndf5 may be a blunder. I still don't see how, so I assume they will reply Ndf5. Indeed, we can continue with g4, Nh4, but I can't see a big win after that, so I assume they will move Ndf5. This also just to contradict you :razz: Joking apart, the other 3 horse moves (4, if Nc2 included) we analyzed, and decided they are white win (not immediately, but the advantage is pretty clear).

Well, the joke is on both of us: [URL="http://mersenneforum.org/showpost.php?p=374078&postcount=145"]28...Nb3[/URL] at 13:22 GMT.

Our deadline: Friday, May 30 11:22 GMT (with the two-hour margin)

[B]29 Rb1 [/B](threatening 30 Rxb3), as previously analyzed.

If [B]29 ... Nxd2 30 Nd6+[/B] (avoiding ... Nxc4, and preventing ... Rxb1)

If [B]30 ... Kf8 31 Rxb8[/B]
If [B]31 ... Bxc3 32 Nxe6+ Kg8 33 Nxc8[/B] and we're exactly one rook up.

If [B]30 ... Kd8 31 Rxb8[/B]
[speculation]
If 31 ... Kc7 32 Rxc8+
If 32 ... Kxd6 33 Nb7+
If 33 ... Kd7 34 Rc5
If 34 ... Nd5 35 Bxd5 exd5 36 Nxa5
If 36 ... Kd6 37 Rb5 Bxc3 38 Kf2

I need to copy over our previous analysis for after 28 ... Nb3.

29. Bf4 may be stronger than the rook move.

[QUOTE=cheesehead;374089]Our deadline: Friday, May 30 11:22 GMT (with the two-hour margin)[/QUOTE]I used a one-hour margin last move, so:

Our deadline: Friday, May 30 12:22 GMT (with one-hour margin)
= Friday, May 30 19:22 Thai time
= Friday, May 30 8:22 EDT
= Friday, May 30 7:22 CDT

Here's our last analysis for the Rb1 response to ... Nb3:

[QUOTE=cheesehead;373006]If 28 ... Nb3 29 Rb1 pins the N/b3 against the R/c8. 29 ... Nxd2 < snip >

30 Nd6+ to avoid losing that knight to 30 ... Nxc4.
Black now has two king moves, but both lead to material loss for Black. (This is a payoff for our having built a strong queen-side position.)
If 30 ... Kd8 31 Rxb8 threatens 32 Nxc8
If 31 ... Kc7 32 Rxc8+ Nxc8
(not 32 ... Kxd6 33 Nb7+
If 33 ... Ke5 34 Rc5+ Kf6 35 Rxa5 and we're up the Exchange plus a pawn,
If 33 ... Kd7 34 Rd8+ Kc7 35 Rxd2 we're a rook up. If now 35 ... Bxc3 36 Rc2 Nd5 37 Bxd5 exd5 38 Nxa5 d4 39 Nb3 and we're still up a rook)
33 Ne8+ Kd8 (or Kb6 34 Nd7+ and 35 Nxg7) 34 Nxg7 e5 and we're a bishop up.
or
If 30 ... Kf8 31 Rxb8, then
If 31 ... Kg8 32 Nxc8 and we're a rook up.
If 31 ... Bxc3 32 Nxc8.
If 31 ... Nc6 or ... Nd5 or ... Nf5 32 Rxc8+)
[/QUOTE]

- - - - - - - - - - - - -

[QUOTE=WMHalsdorf;374115]29. Bf4 may be stronger than the rook move.[/QUOTE]I don't see that we ever analyzed the Bf4 response to 28 ... Nb3, but here's our last analysis for the Bf4 response to 28 ... Nec6 (I've debolded all moves and underlined 28 ... Nec6):
[U] Note: the following is not analysis we can use directly now, but is posted only as a possible source of ideas for [/U][U]the Bf4 response to 28 ... Nb3[/U][QUOTE=cheesehead;373263]28 Re1 [U]Nec6[/U] 29 Bf4 threatens 30 Bxb8 and the rook's only "safe" move is 29 ... Ra8, but that still leaves the rook on our B/g2's long diagonal.
If 29 ... Ra8 30 Nb6 Ra7 31 Nxc8
If 31 ... Ra8 32 Nd6+
If 32 ... Kd8 or Kf8 33 cxd4 Bxd4+ 34 Be3
If 32 ... Ke7 33 cxd4 Bxd4+ 34 Be3 Bxe3+ 35 Rxe3 Kxd6 36 Rxe6+ Kxc5 37 Rxc6+ Kb4 38 Rb6+ (or 37 ... Kd4 38 Rd6+). Now, no matter where the king moves, 39 Bxa8 leaves us at least a bishop up in a winning endgame.
If 31 ... Rf7 32 Nd6+ and 33 Nxf7
If 29 ... e5 the e-pawn is pinned, and thus can't immediately capture with 30 ... exf4, but it does block the B/f4's attack on the R/b8. Then
30 cxd4 puts us up a piece and threatens 31 Bxc6+, but our b4 square is no longer guarded against Rb4.
If 30 ... Nxd4 31 Nxe5 threatens 32 Nc6+ and 33 Nxc8.
If 31 ... Kf8 (not ... Kd8 32 Nf7++ or Nc6++) 32 Ned7+ Bxd7 33 Nxd7+ K-moves 33 Bxc8 or Nxc8[/QUOTE][U] Note: the preceding is not analysis we can use directly now, but is posted only as a possible source of ideas for [/U][U]the Bf4 response to 28 ... Nb3.
[/U]

So, let's analyze the Bf4 response to 28 ... Nb3:

[B]29 Bf4[/B] (threatens 30 Bxb8 and the rook has _no_ "safe" move).

Black could move the rook, block the f4-b8 diagonal, play some other forcing move strong enough to make us pass up Bxc8 ... or just lose the Exchange with 29 ... Nxc5 30 Bxc8.

If [B]29 ... R-moves[/B] we simply capture the rook with 30 Bxa8 or Nxb7 or Bxb7 or Nxb6 or axb5 or cxb4.

The only blocking Black moves are 29 ... Be5 and 29 ... e5:
If [B]29 ... Be5 30 Bxe5[/B] - we're a bishop up and our threats to capture the rook remain.
If [B]29 ... e5 30 Bxe5[/B] (not 30 Nxe5 Nxc5) [B]Bxe5 31 Rxe5[/B] (not 31 Nxe5 Nxc5) [strike]we're up a pawn.[/strike] [U]Wait! I need to look closer at 31 Ne5 Nxc5.[/U]
Black doesn't seem to have any forcing move strong enough to make us pass up Bxc8.
If [B]29 ... Nxc5 30 Bxb8[/B]

[strike]So, Black's strongest moves in the Bf4 line
[B](29 Bf4 e5 30 Bxe5 Bxe5 31 Rxe5)[/B] seem to allow us to win only a pawn.
Have I overlooked something?

If not, then [B]29 Rb1[/B] leads to greater material gain.[/strike]