An idea for a different type of tournament

[jp]

I ran Stockfish dev on the position with only king and pawns for black

SF can show a faster mate than your mate in 16 with my slow hardware (mate in 15).

FEN: 4k3/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1

Stockfish_20021515_x64_modern:
<snip>
46/32 11:05 3,054,954k 4,588k +M15 1.e3 g6 2.Qg4 a6 3.Qd4 d6 4.Qa7 c6 5.Qxb7 Kf8 6.Qxc6 Kg7 7.Qd7 Kf6 8.Nc3 d5 9.Nf3 a5 10.Nxd5+ Kg7 11.Qxe7 g5 12.Nxg5 Kg6 13.Qxf7+ Kxg5 14.Qf6+ Kg4 15.Be2+
47/30 11:43 3,227,612k 4,591k +M15 1.e3 g6 2.Qg4 a6 3.Qd4 d6 4.Qa7 c6 5.Qxb7 Kf8 6.Qxc6 Kg7 7.Qd7 e6 8.Qxd6 a5 9.Nf3 g5 10.Qe7 g4 11.Ne5 a4 12.Qxf7+ Kh6 13.Nxg4+ Kg5 14.h4+ Kxg4 15.Be2+
48/30 13:24 3,660,153k 4,550k +M15 1.e3 g6 2.Qg4 a6 3.Qd4 d6 4.Qa7 c6 5.Qxb7 Kf8 6.Qxc6 Kg7 7.Qd7 e6 8.Qxd6 a5 9.Nf3 g5 10.Qe7 g4 11.Ne5 a4 12.Qxf7+ Kh6 13.Nxg4+ Kg5 14.h4+ Kxg4 15.Be2+
49/30 14:37 3,975,783k 4,531k +M15 1.e3 g6 2.Qg4 a6 3.Qd4 d6 4.Qa7 c6 5.Qxb7 Kf8 6.Qxc6 Kg7 7.Qd7 e6 8.Qxd6 g5 9.Qe7 g4 10.Nf3 e5 11.Nxe5 a5 12.Qxf7+ Kh6 13.Qf6+ Kh5 14.Be2 a4 15.Bxg4+

That's a good result. Maybe the latest SF dev version is much improved. (I see you've used the one just released.)

It looks like 1....g6 instead of 1...h6 doesn't slow mate for Black.

1. e3 h6 2. Qh5 c6 ...

[If you make SF10 look at the position after] 2. Qh5:

2... a6 3. Qe5 d6 4. Qxg7 e5 5. Qg8+ Ke7 6. Qc8 c6 7. Qxb7+ Ke8 8. Bc4 d5 9. Qxc6+ Kf8 10. Qxd5 Ke7 11. Qxf7+ Kd6 12. Bd5 e4 13. Nc3 a5 14. Nxe4+ Ke5 15. Qe6#

So is it really mate in 15?

[jp]

r3k3/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQq - 0 1

59/50 1:49:41 398,262,715k 60,513k +M25 e2-e3 g7-g6 Qd1-g4 c7-c6 Qg4-h4 h7-h5 Qh4-d4 f7-f6 Qd4-d3 Ke8-d8 Qd3xg6 Kd8-c7 Qg6xh5 Ra8-f8 Qh5-h7 Kc7-d8 Qh7-g7 Rf8-e8 Ng1-f3 Kd8-c7 Qg7-f7 Kc7-d8 Bf1-d3 Re8-h8 Bd3-g6 a7-a6 Qf7-g7 Rh8-h5 Bg6xh5 a6-a5 Qg7-f8+ Kd8-c7 Qf8xe7 a5-a4 Bh5-g6 a4-a3 Nb1xa3 f6-f5 Nf3-e5 f5-f4 e3xf4 Kc7-b6 Qe7-d8+ Kb6-a7 Ne5xd7 b7-b6 Qd8xb6+ Ka7-a8 Qb6-a6+

It traps the rook. I bet there is a faster mate.

I haven't run it much longer than this.

Was that still SF11?

[mmt]

Was that still SF11?

Yes.

[jp]

SF can show ... (mate in 15).

FEN: 4k3/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1

Stockfish_20021515_x64_modern:
<snip>
46/32 11:05 3,054,954k 4,588k +M15 1.e3 g6 2.Qg4 a6 3.Qd4 d6 4.Qa7 c6 5.Qxb7 Kf8 6.Qxc6 Kg7 7.Qd7 Kf6 8.Nc3 d5 9.Nf3 a5 10.Nxd5+ Kg7 11.Qxe7 g5 12.Nxg5 Kg6 13.Qxf7+ Kxg5 14.Qf6+ Kg4 15.Be2+
47/30 11:43 3,227,612k 4,591k +M15 1.e3 g6 2.Qg4 a6 3.Qd4 d6 4.Qa7 c6 5.Qxb7 Kf8 6.Qxc6 Kg7 7.Qd7 e6 8.Qxd6 a5 9.Nf3 g5 10.Qe7 g4 11.Ne5 a4 12.Qxf7+ Kh6 13.Nxg4+ Kg5 14.h4+ Kxg4 15.Be2+
48/30 13:24 3,660,153k 4,550k +M15 1.e3 g6 2.Qg4 a6 3.Qd4 d6 4.Qa7 c6 5.Qxb7 Kf8 6.Qxc6 Kg7 7.Qd7 e6 8.Qxd6 a5 9.Nf3 g5 10.Qe7 g4 11.Ne5 a4 12.Qxf7+ Kh6 13.Nxg4+ Kg5 14.h4+ Kxg4 15.Be2+
49/30 14:37 3,975,783k 4,531k +M15 1.e3 g6 2.Qg4 a6 3.Qd4 d6 4.Qa7 c6 5.Qxb7 Kf8 6.Qxc6 Kg7 7.Qd7 e6 8.Qxd6 g5 9.Qe7 g4 10.Nf3 e5 11.Nxe5 a5 12.Qxf7+ Kh6 13.Qf6+ Kh5 14.Be2 a4 15.Bxg4+

Previously I also removed White's Rs and QB (because they weren't being used in SF's lines; I doubt it makes any difference):

[d]4k3/pppppppp/8/8/8/8/PPPPPPPP/1N1QKBN1 w - - 0 1

After 1.e3 h6 2. Qf3,
SF10 shows mate by move 15 (with ...c6 best):

2...c6 3. Qg3 e5 4. Qxe5+ Kd8 5. Qb8+ Ke7 6. Qxb7 h5 7. Qxa7 g5 8. Nf3 f6 9. Nd4 g4 10. Nf5+ Ke6 11. e4 h4 12. Nc3 Kf7 13. Qxd7+ Kg6 14. Qg7+ Kh5 15. Qh6#
2... e6 3. Qxb7 g5 4. Qxc7 a6 5. Qd6 g4 6. Bxa6 f5 7. Bb5 Kf7 8. Qxd7+ Kf6 9. Bc4 h5 10. Qxe6+ Kg7 11. Qg8+ Kf6 12. Qf7+ Kg5 13. Qg7+ Kh4 14. g3#
2... g5 3. Qxb7 e6 4. Nf3 f6 5. Qxc7 a6 6. Bxa6 g4 7. Bb5 gxf3 8. Qxd7+ Kf8 9. Qxe6 h5 10. Bc4 Kg7 11. Qg8+ Kh6 12. Bf7 fxg2 13. Qg6#
2... d5 3. Qxd5 c6 4. Qe5 Kd7 5. Qb8 b5 6. Nf3 f6 7. Bd3 g5 8. Nd4 e6 9. Qb7+ Kd6 10. Qxc6+ Ke7 11. Qc7+ Ke8 12. Nxe6 a5 13. Bxb5#
2... e5 3. Qxb7 Kd8 4. Qb8+ Ke7 5. Qxc7 a6 6. Bxa6 g5 7. Qxe5+ Kf8 8. Nc3 g4 9. Nd5 Kg8 10. Ne7+ Kf8 11. Nf5 f6 12. Qxf6+ Kg8 13. Qg7#
2... Kf8 3. Qxb7 g5 4. Qxc7 g4 5. Qd8+ Kg7 6. Qxe7 d5 7. Ne2 d4 8. Nf4 g3 9. hxg3 dxe3 10. Ne6+ Kg6 11. Bd3+ f5 12. Nf4#

The 1.e3 g6 2.Qg4 lines may be more difficult for SF to complete.

[jp]

(With White's pieces restored, Black still with only pawns)
After 1. e3 g6 2. Qg4 a6 3. Qd4,
SF10 shows mate by move 14:

3. ... d6 4.Qa7 c6 5.Qb8+ Kd7 6.Qxb7+ Ke6 7.Bc4+ Kf6 8.b4 d5 9.Bb2+ e5 10.Bxe5+ Kxe5 11.Qe7+ Kf5 12.Bd3+ Kg4 13.Be2+ Kf5 14.g4#
3 ... f6 4. Qc4 e6 5. Qxc7 h5 6. b3 b5 7. Ba3 b4 8. Bxb4 g5 9. Qb8+ Kf7 10. Qf8+ Kg6 11. Qg8+ Kf5 12. Bd3+ Kg4 13. f3+ Kh4 14. g3#
3 ... e6 4.Qc5 g5 5.b3 b6 6.Qxc7 b5 7.Ba3 b4 8.h4 gxh4 9.Rxh4 h5 10.Rxh5 a5 11.Qd6 f5 12.Rh7 bxa3 13.Qe7#
3 ... d5 4. b3 Kd7 5. Ba3 Kd8 6. Qxd5+ Ke8 7. Qc5 Kd7 8. Qxe7+ Kc6 9. Be2 b5 10. Bf3+ Kb6 11. Bc5+ Ka5 12.Qxc7#
3 ... f5 4.Qh8+ Kf7 5.Nf3 h6 6.Bc4+ d5 7.Ne5+ Ke6 8.Qg8+ Kxe5 9.f4+ Kf6 10.Bxd5 e6 11.Qf8#
3 ... e5 4. Qxe5+ Kf8 5. Qf6 b5 6. Nf3 d6 7. Ng5 Ke8 8. Qxf7+ Kd8 9. Ne6+ Kc8 10. Qxc7#

So Black loses more quickly after 1... g6 2... a6 (than after 1... h6 2... c6). Again, SF's mate announcement (mate in 15) doen't show the best defence in its PV, because it's not searching all of the attacking moves.

[jp]

Here is another example
Stockfish needed a lot of time to find e4 and not e3 and could not see it at depth<95 (I used 1024 mbytes hash and 3 cores)
Note that chest with a single core was faster in seeing e4 is the only move that force mate in 8.

[d]1n2k3/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1

Stockfish_20030109_x64_modern:
<snip>
94/18 08:44 3,206,095k 6,111k +M9 1.e3 Ke7 2.Bb5 Nd7 3.Qg4 Nf6 4.Qg7+ Ke6 5.Nc3 Kd6 6.Qxf6+ Kc7 7.Qc6+ Kb8 8.Ba6 Ka7 9.Qb7+
95/18 10:54 4,041,755k 6,171k +M8 1.e4 Nc6 2.Qh5+ Ke7 3.Qc5+ Kd7 4.d4 Nb4 5.Bb5+ Ke6 6.Qf5+ Ke7 7.Bg5+ Kd6 8.Qe5+

Komodo 13.2 shows mate in 8 from depth 21:

+M8 1.e4 Nd7 2.d4 Nf6 3.Qf3 Nd7 4.Bg5 Ne5 5.Bb5+ Nd7 6.Qh5+ Kf8 7.Bc4 Nf6 8.Qf7#

Surely this is largely luck, though, i.e. whether a given engine happened to like 1.e4 early, before the depths when it started announcing mates?

[jp]

For the N on the other side,

[d]4k1n1/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1

Komodo 13.2 does like 1.e3 to begin with, and switches to

+M8 1.e4 Nf6 2.Qf3 Nd7 3.d4 Kd8 4.Qf7 Kc7 5.Bf4+ Kc8 6.Ba6+ Kd8 7.Bb7 Ne5 8.Bg5#

around depth 25.

SF10 takes till depth 47 to find mate in 9 (with 1.e3) and did not find the mate in 8 at depths <=67.

Sf-dev finds mate-in-8 at depth 52 (one thread, 16 GB hash)

info depth 52 seldepth 18 multipv 1 score mate 8 nodes 34076245 nps 2512071 hashfull 12 tbhits 0 time 13565 pv d2d4 g8f6 e2e4 e8d8 d1f3 f6e8 f3f8 d8d7 c1f4 d7e6 f1b5 e8f6 c2c4 f6e4 d4d5

[jp]

[d]1n2k1n1/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1

Komodo 13.2 finds mate in 11:

depth=22 +M12 1.e4 Nf6 2.e5 Nd5 3.Qg4 Ne7 4.Bb5+ Kd8 5.Qh4 Nc6 6.Bxc6 Kc7 7.Qxe7+ Kxc6 8.Qd6+ Kb7 9.e6 Ka7 10.e7 Kb7 11.e8=Q Ka7 12.Qeb8#

depth=23 +M11 1.e4 Nf6 2.Qf3 Nfd7 3.d4 Ke7 4.Bg5+ Kd6 5.Bd8 Nc6 6.Qf4+ Nde5 7.dxe5+ Kd7 8.e6+ Kxd8 9.Qd6+ Ke8 10.Qd7+ Kf8 11.Qf7#


SF10 find it around depth 32:

depth=33 +M11 1.e4 Nf6 2.d4 Nc6 3.Qf3 Ng8 4.Qh5+ Ke7 5.Bc4 Nf6 6.Qf7+ Kd8 7.Bg5 Ne7 8.Qxf6 Kc7 9.Qxe7+ Kb6 10.Qd7 Ka5 11.Qb5#

[d]1nb1k3/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1

Komodo 13.2 finds mate in 11 by depth 20:

+M11 1.e4 Ba6 2.Qh5+ Kd8 3.Qa5+ Ke8 4.Bxa6 Nc6 5.Qb6 Kd7 6.d4 Ne7 7.Bg5 Nc6 8.Qb7+ Kd6 9.Bf4+ Ne5 10.Bxe5+ Ke6 11.Bc4#

SF10 can only find mate in 12 up to depths in the 50s.

[jp]

[d]2b1kb2/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1

Komodo 13.2:

depth=24 +M11 1.e4 Kd8 2.Qh5 Bd6 3.Nc3 Bb7 4.Bb5 Kc7 5.Qe8 Bf4 6.Nd5+ Bxd5 7.exd5 Kb6 8.Qc6+ Ka7 9.Ba6 Bxd2+ 10.Bxd2 Kb8 11.Qb7#

SF10 can find only mate in 12 to depth 60:

depth=43 +M12 1.e3 Bd7 2.Nc3 Bc6 3.Qg4 Kd8 4.Qd4+ Kc7 5.Nb5+ Kc8 6.Qh8 Bxb5 7.Bxb5 Kb7 8.Qxf8 Ka7 9.Qe7+ Kb6 10.c4 Ka5 11.Qa7+ Kb4 12.Qa3#

[jp]

[d]r3k2r/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

SF10's best up to depth 56 is mate in 14:

depth=55 +M14 1.e3 Ra5 2.Qg4 Rhh5 3.Nc3 Rag5 4.Qe6+ Kd8 5.Nf3 Rf5 6.Nd4 Rfg5 7.Qf6+ Ke8 8.Bc4 Rh7 9.Qxg5 Re7 10.Nd5 Re4 11.Qg8+ Kd7 12.Qg7+ Re7 13.Qxe7+ Kc8 14.Qc7#

depth=56 +M14 1.e3 Ra5 2.Qg4 Rhh5 3.Nc3 Rag5 4.Qe6+ Kd8 5.Nf3 Rc5 6.Nd4 Rhe5 7.Nc6+ Rxc6 8.Qxe5 Rc7 9.Bb5 Kc8 10.Qd6 Kb7 11.Ba6+ Ka7 12.Nb5+ Ka8 13.Qd8+ Rc8 14.Qxc8#