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Subject: Re: Mate in 9 -- NOPE, It's a Mate in 8!

Author: John Merlino

Date: 18:04:43 06/17/02

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On June 17, 2002 at 20:42:28, Jeremiah Penery wrote:

>On June 17, 2002 at 20:16:01, John Merlino wrote:
>
>>Here's an amusing little Mate in 9 King chase that I had when testing
>>Chessmaster 9000:
>>
>>[D]r6r/ppp1bQpp/2k1B1q1/4P3/4p3/2P1B3/PP3P1P/2K2R2 w - - 0 20
>>
>>Chessmaster announces Mate in 10 in three seconds on my PIII-600, then switches
>>to Mate in 9 after ten seconds:
>>
>>Time	Depth	Score	Positions	Moves
>>0:00	1/3	5.29	2701		20.Qxe7 b6 21.Qd7+ Kb7 22.Bd5+
>>					Kb8 23.Bxa8 Kxa8 24.Qxc7
>>0:00	1/3	5.65	5976		20.Rd1 b6 21.Qxe7 Kb7 22.Bd5+ Kb8
>>					23.Bxa8 Kxa8 24.Qxc7
>>0:00	1/4	5.19	11659		20.Rd1 b6 21.Qxe7 Rhd8 22.Rxd8
>>					Rxd8 23.Qxd8 Qxe6 24.Qa8+ Kb5 25.Qxe4
>>					Qxa2 26.Qxh7
>>0:01	2/5	14.85	74968		20.Rd1 b6 21.Bd5+ Kb5 22.Qxe7 Qd6
>>					23.exd6 Raf8 24.Bxe4
>>0:01	2/6	15.35	145320		20.Rd1 b6 21.Bd5+ Kb5 22.Qxe7 Qd6
>>					23.exd6 c6 24.c4+ Ka6 25.Bxc6
>>0:03	3/7	Mate10	374294		20.Rd1 b6 21.Bd5+ Kb5 22.Bc4+ Ka5
>>					23.Qxe7 c5 24.Qd7 a6 25.b4+ cxb4
>>					26.Rd5+ b5 27.Rxb5+ Ka4 28.Rxb4+
>>					Ka5 29.Qa4#
>>0:10	3/8	Mate09	1098190		20.Rd1 b6 21.Bd5+ Kb5 22.Bc4+ Ka5
>>					23.Qd5+ Bc5 24.Bxc5 Qg5+ 25.Kc2
>>					Qd2+ 26.Rxd2 bxc5 27.Qxc5+ Ka4
>>					28.Qb4#
>>
>>Since four of the nine moves are not checking moves, can anybody else do better?
>
>Here's an interesting result.  Not as fast as CM (almost 50 times slower, given
>the hardware difference) to find mate, but it finds a shorter one.  This is
>modified Crafty 18.15 with singular extensions, AthlonXP 1600MHz:
>
>analyze.Black(1): r6r/ppp1bQpp/2k1B1q1/4P3/4p3/2P1B3/PP3P1P/2K2R2 w - - 0 20
>              clearing hash tables
>              time surplus   0.00  time limit 30.00 (3:30)
>         nss  depth   time  score   variation (1)
>                6     0.32     ++   1. Rd1!!
>                6     0.77   9.57   1. Rd1 b6 2. Bd5+ Kb5 3. Qxe7 c5 4.
>                                    c4+ Ka6 5. Qb7+ Ka5 6. Bd2+ Ka4 7.
>                                    Bxe4 <HT>
>                6->   0.84   9.57   1. Rd1 b6 2. Bd5+ Kb5 3. Qxe7 c5 4.
>                                    c4+ Ka6 5. Qb7+ Ka5 6. Bd2+ Ka4 7.
>                                    Bxe4 <HT>
>                7     1.54     ++   1. Rd1!!
>                7     6.58  14.16   1. Rd1 b6 2. Bd5+ Kd7 3. Bb7+ Qd6 4.
>                                    Qf5+ Kd8 5. exd6 cxd6 6. Bxa8 Kc7 7.
>                                    Bd5 Kb8 8. Qxe4
>                7->   6.78  14.16   1. Rd1 b6 2. Bd5+ Kd7 3. Bb7+ Qd6 4.
>                                    Qf5+ Kd8 5. exd6 cxd6 6. Bxa8 Kc7 7.
>                                    Bd5 Kb8 8. Qxe4
>                8     9.93     ++   1. Rd1!!
>                8    16.26  17.17   1. Rd1 b6 2. Bd5+ Kb5 3. Qxe7 Qd6 4.
>                                    exd6 c6 5. c4+ Ka6 6. Bxc6 Rad8 7.
>                                    Qb7+ Ka5 8. Qxa7+
>                8->  16.82  17.17   1. Rd1 b6 2. Bd5+ Kb5 3. Qxe7 Qd6 4.
>                                    exd6 c6 5. c4+ Ka6 6. Bxc6 Rad8 7.
>                                    Qb7+ Ka5 8. Qxa7+
>                9    26.31     ++   1. Rd1!!
>                9    46.19  Mat09   1. Rd1 b6 2. Bd5+ Kb5 3. Qxe7 a5 4.
>                                    Qxc7 Rac8 5. Bc4+ Ka4 6. Bb3+ Kb5 7.
>                                    Rd5+ Ka6 8. Bc4+ b5 9. Bxb5#
>                9->  48.39  Mat09   1. Rd1 b6 2. Bd5+ Kb5 3. Qxe7 a5 4.
>                                    Qxc7 Rac8 5. Bc4+ Ka4 6. Bb3+ Kb5 7.
>                                    Rd5+ Ka6 8. Bc4+ b5 9. Bxb5#
>               10     1:15  Mat08   1. Rd1 b6 2. Bd5+ Kb5 3. Qxe7 a5 4.
>                                    Qxc7 Rac8 5. Bc4+ Ka4 6. Kb1 Rxc7 7.
>                                    b3+ Ka3 8. Bc1#
>               10->   1:21  Mat08   1. Rd1 b6 2. Bd5+ Kb5 3. Qxe7 a5 4.
>
>
>Is the given line correct?

It is correct! I guess I didn't let the analysis go long enough. It is a Mate in
8, which Chessmaster 9000 will announce in 1:48 on my PIII-600:

Time	Depth	Score	Positions	Moves
0:00	1/3	5.29	2709		20.Qxe7 b6 21.Qd7+ Kb7 22.Bd5+
					Kb8 23.Bxa8 Kxa8 24.Qxc7
0:00	1/3	5.65	5984		20.Rd1 b6 21.Qxe7 Kb7 22.Bd5+ Kb8
					23.Bxa8 Kxa8 24.Qxc7
0:00	1/4	5.19	11667		20.Rd1 b6 21.Qxe7 Rhd8 22.Rxd8
					Rxd8 23.Qxd8 Qxe6 24.Qa8+ Kb5 25.Qxe4
					Qxa2 26.Qxh7
0:01	2/5	14.85	75172		20.Rd1 b6 21.Bd5+ Kb5 22.Qxe7 Qd6
					23.exd6 Raf8 24.Bxe4
0:01	2/6	15.35	145579		20.Rd1 b6 21.Bd5+ Kb5 22.Qxe7 Qd6
					23.exd6 c6 24.c4+ Ka6 25.Bxc6
0:04	3/7	Mate10	374470		20.Rd1 b6 21.Bd5+ Kb5 22.Bc4+ Ka5
					23.Qxe7 c5 24.Qd7 a6 25.b4+ cxb4
					26.Rd5+ b5 27.Rxb5+ Ka4 28.Rxb4+
					Ka5 29.Qa4#
0:10	3/8	Mate09	1094329		20.Rd1 b6 21.Bd5+ Kb5 22.Bc4+ Ka5
					23.Qd5+ Bc5 24.Bxc5 Qg5+ 25.Kc2
					Qd2+ 26.Rxd2 bxc5 27.Qxc5+ Ka4
					28.Qb4#
0:29	4/9	Mate09	3138341		20.Rd1 b6 21.Bd5+ Kb5 22.Bc4+ Ka5
					23.Qd5+ Bc5 24.Bxc5 Qg5+ 25.Kc2
					Qd2+ 26.Rxd2 bxc5 27.Qxc5+ Ka4
					28.Qb5#
1:48	4/10	Mate08	12212845	20.Rd1 b6 21.Bd5+ Kb5 22.Qxe7 a5
					23.Qxc7 Rac8 24.Bc4+ Ka4 25.Kb1
					Rxc7 26.b3+ Ka3 27.Bc1#

Sorry about that!

jm



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