Shredder 10 doesn't see 73.Rxf1

[Uri]

[d] 8/8/6K1/8/8/8/8/R4qkr w - - 0 73

Although this position is clearly lost for white because of material, white can hold out longer with 73.Rxf1. I was surprised to find out that Shredder 10 doesn't find this simple move but Rybka 3 and Chessmaster 9000 find it immediately.

[sje]

From bad to worst, the moves ranked:

• Rxf1+ TBScore: LoseIn15
  Ra5 TBScore: LoseIn8
  Ra7 TBScore: LoseIn8
  Ra2 TBScore: LoseIn7
  Ra3 TBScore: LoseIn7
  Ra4 TBScore: LoseIn7
  Ra8 TBScore: LoseIn7
  Kg5 TBScore: LoseIn6
  Rb1 TBScore: LoseIn6
  Rc1 TBScore: LoseIn6
  Rd1 TBScore: LoseIn6
  Kg7 TBScore: LoseIn5
  Ra6 TBScore: LoseIn5
  Re1 TBScore: LoseIn5

[Ferdy]

[d] 8/8/6K1/8/8/8/8/R4qkr w - - 0 73

Although this position is clearly lost for white because of material, white can hold out longer with 73.Rxf1. I was surprised to find out that Shredder 10 doesn't find this simple move but Rybka 3 and Chessmaster 9000 find it immediately.

The decision to retain the rook is also reasonable, how can white win if white rook is gone

[bob]

[d] 8/8/6K1/8/8/8/8/R4qkr w - - 0 73

Although this position is clearly lost for white because of material, white can hold out longer with 73.Rxf1. I was surprised to find out that Shredder 10 doesn't find this simple move but Rybka 3 and Chessmaster 9000 find it immediately.

I'd bet it is caused by endgame tables. After Rxf1 Kxf1 it probably probably sees the mate due to endgame tables, while keeping all 5 pieces on the board causes it to not see the forced mate.

Do you have all or some endgame tables?

[Uri]

Do you have all or some endgame tables?

No i don't use any endgame tables. My computer is slow and they take a lot of access time.

[Nimzovik]

contempt factor settong?

[Uri]

contempt factor settong?

No. There is no contempt factor in Shredder 10

[BubbaTough]

Shredder just has a big eval bonus for KR v. K as a known won situation. Quite a reasonable thing to do. Its as simple as that.

-Sam

[Kurt Utzinger]

Shredder just has a big eval bonus for KR v. K as a known won situation. Quite a reasonable thing to do. Its as simple as that.
-Sam

I think you are right. Such positions are in some way interesting but of not much practical relevance.
Kurt

[Graham Banks]

Shredder just has a big eval bonus for KR v. K as a known won situation. Quite a reasonable thing to do. Its as simple as that.
-Sam

I think you are right. Such positions are in some way interesting but of not much practical relevance.
Kurt

Agreed.