Author: Heiner Marxen
Date: 09:02:09 03/02/02
Go up one level in this thread
On March 02, 2002 at 10:54:41, leonid wrote:
>On March 02, 2002 at 10:07:36, Tim Foden wrote:
>
>>On March 02, 2002 at 08:21:10, leonid wrote:
>>
>>>[D]3Q3R/Q2b2Q1/1Q1q1Q2/1qQqQq1B/Nr1q1rNB/2qkq3/1qnbnq2/Q2K2QR w - -
>>>
>>>Please indicate your result.
>>>
>>Green Light Chess v2.16, 48MB Hash, Athlon XP 1700+ says Mate in 9 after just
>>over 13.5 minutes.
>>
>>Cheers, Tim.
>
>Hi, Tim!
>
>Are you sure about 9 moves solution? Or I tried some different position from
>what is here, or you put wrong on your side. This position mine looked 9 moves
>deep by brute force and found no mate. I don't know exactly shortest mate for
>it. It was solved by 11 moves by selective and searched only 9 moves deep by
>brute force. I can see 9 moves only during this night, since it took already 4.5
>hours. It could be that Heiner, with speedier computer and hash, will say
>shortest mate before this.
>
>Cheers,
>Leonid.
>
Hi Tim, Hi Leonid,
Chest confirms that there is not mate-in-9.
Since that was my initial guess, I just restarted with depth=11.
For depth=9 I needed 19.2 minutes (K7/600 350MB hash).
The faster box is at work, not here at home, sorry.
>>>anal
>> Game stage: Opening
>> Current eval: -0.685
>> Ply Time Score Nodes Principal Variation
>> 1 0.06 +15.973 13553 Nxb2+ Rxb2 2. Nxf2+
>> 2 0.10 +16.152 38665 Nxb2+ Rxb2 2. Qbxd6
>> 2 0.38 +16.152 218218 Nxb2+ Rxb2 2. Qbxd6
>> 3 0.38 +16.552 220805 Nxb2+ Rxb2 2. Nxf2+ Qxf2 3. Qcxd6 {++}
>> 3 0.64 +22.415 430008 Nxb2+ Rxb2 2. Nxf2+ Rxf2 3. Qbxd6 Qbxc5 4. Qfxf5+
>> 3 2.26 +22.415 1781082 Nxb2+ Rxb2 2. Nxf2+ Rxf2 3. Qbxd6 Qbxc5 4. Qfxf5+
>> 4 8.67 +22.126 7320735 Nxb2+ Qxb2 2. Nxf2+ Rxf2 3. Qbxb5+ Rxb5 4. Bxe2+
>> Qxe2+ 5. Qxe2+ Rxe2 6. Qxf5+ Bxf5 7. Qg1xd4+ Nxd4
>> 8. Qxd5 Rxd5 9. Qxb2
>> 4 29.51 +22.126 24640k Nxb2+ Qxb2 2. Nxf2+ Rxf2 3. Qbxb5+ Rxb5 4. Bxe2+
>> Qxe2+ 5. Qxe2+ Rxe2 6. Qxf5+ Bxf5 7. Qg1xd4+ Nxd4
>> 8. Qxd5 Rxd5 9. Qxb2
>> 5 30.89 +22.526 25662k Nxb2+ Qxb2 2. Nxf2+ Rxf2 3. Qbxb5+ Rxb5 4. Bxe2+
>> Qxe2+ 5. Qxe2+ Rxe2 6. Qxf5+ Bxf5 7. Qg1xd4+ Nxd4
>> 8. Qcxd4+ Qbxd4 9. Qa1xd4+ Qxd4 10. Qaxd4+ {ht}
>> {++}
>> 5 1:25 +32.728 69902k Nxb2+ Qxb2 2. Nxf2+ Rxf2 3. Bxe2+ Rxe2 4. Qfxf5+
>> Qd5e4 5. Qexe4+ Qexe4 6. Qxe4+ Kxe4 7. Qde7+ Qxe7
>> 8. Qgxe7+ Qe5 9. Qxb2
>> 5 8:06 +32.728 384947k Nxb2+ Qxb2 2. Nxf2+ Rxf2 3. Bxe2+ Rxe2 4. Qfxf5+
>> Qd5e4 5. Qexe4+ Qexe4 6. Qxe4+ Kxe4 7. Qde7+ Qxe7
>> 8. Qgxe7+ Qe5 9. Qxb2
>> 6 8:30 +33.128 403239k Nxb2+ Qxb2 2. Nxf2+ Rxf2 3. Bxe2+ Rxe2 4. Qfxf5+
>> Qd5e4 5. Qexe4+ Qexe4 6. Qxe4+ Kxe4 7. Q7g6+ Kf4
>> 8. Qcxd6+ Kf3 9. Qxb2 {++}
>> 6 13:24 +Mate09 782417k Nxb2+ Qxb2 2. Nxf2+ Rxf2 3. Bxe2+ Rxe2 4. Qcxd4+
>> Qexd4 5. Qgxd4+ Nxd4 6. Qxb5+ Kc3 7. Qexd4+ Qxd4
>> 8. Qfxd4+ {ht}
>> 6 35:16 +Mate09 2669m Nxb2+ Qxb2 2. Nxf2+ Rxf2 3. Bxe2+ Rxe2 4. Qcxd4+
>> Qexd4 5. Qgxd4+ Nxd4 6. Qxb5+ Kc3 7. Qexd4+ Qxd4
>> 8. Qfxd4+ {ht}
According to Chest, after 1.Nxb2+ Rxb2 there is a mate-in-8 to follow up,
but not after 1.Nxb2+ Qxb2.
Ok, lets follow that line, as far as you give it. After 7 moves, where your
programs gives 8. Qfxd4+, what should be a mate-in-2, we have
[D]3Q3R/Q2b2Q1/3q1Q2/1Q3q2/1r1q3B/2k5/1q1br3/Q2K3R w - -
This is a mate-in-2 with 8.Q7a3+ Rb3 9.Qbxb3#, but after 8. Qfxd4+
black may do 8...Qxd4 after which there is no mate move. After the other
two legal black moves, 8...Rxd4 and 8...Kb3 there are mate moves available.
So, something is wrong at your side, I guess. But since we have a mate,
something else must be wrong, too. Lets go on:
After 6 of your moves we have
[D]3Q3R/Q2b2Q1/3q1Q2/1Q1qQq2/1r1n3B/2k5/1q1br3/Q2K3R w - -
which is a mate in 3 with solution
Qexd4+ Qxd4 Q7a3+ Rb3 Qbxb3#
Rxd4 Qaxb2#
Kb3 Qdxb2#
Ok.
After 5 of your moves we have
[D]3Q3R/Q2b2Q1/1Q1q1Q2/1q1qQq2/1r1n3B/3k4/1q1br3/Q2K3R w - -
and, according to Chest, no mate-in-4, as your line would need.
Your program gave 6.Qxb5+ Kc3, which we see above, but what after
6.Qxb5+ Qxb5 ? No mate in 3 is available, here.
That should be enough stuff for you to search for a bug. Or you had a
slightly different position. Check against the FENs above.
Cheers anyhow,
Heiner
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