### Longest Win for each Bishop Combination?

Posted:

**Fri Aug 09, 2013 11:09 pm**Instead of finding the absolute longest win of an endgame, does anyone know of a way to find the longest win for each combination of bishops?

Even in endgames with only one bishop, there will often be two types of wins (if it is a normally drawn endgame): one where the defender's king is near a corner that is the same color as the bishop, and one where it is not. Since these types of endgames are normally draws when the defender's king is near the center, the two types of wins tend to never be sub-variations of the same position, so it is important to know the longest win for each.

Example: The longest wins in KRB vs. KR are DTC59

7K/R7/4k3/8/1b6/8/3r4/8 b - - 0 1

and

5k2/3K4/8/5r2/1R6/8/3B4/8 w - - 0 1

The bishop is the same color as the corner in both positions, and the simple Philidor Position is eventually reached in both. Is there a way to find the longest win where the bishop is NOT the same color as the corner? So far, the longest win I've found is 7K/1r6/8/R2bk3/8/8/8/8 b - - 0 1 where the simple Lolli Position is eventually reached. I've never found a position where both the Philidor and Lolli positions are sub-variations of the same position.

Another long endgame with a similar bishop problem is KBN vs. KN, because the longest wins will be completely different depending on the color of the bishop compared to the corner that the defender's king is near.

Even in endgames with only one bishop, there will often be two types of wins (if it is a normally drawn endgame): one where the defender's king is near a corner that is the same color as the bishop, and one where it is not. Since these types of endgames are normally draws when the defender's king is near the center, the two types of wins tend to never be sub-variations of the same position, so it is important to know the longest win for each.

Example: The longest wins in KRB vs. KR are DTC59

7K/R7/4k3/8/1b6/8/3r4/8 b - - 0 1

and

5k2/3K4/8/5r2/1R6/8/3B4/8 w - - 0 1

The bishop is the same color as the corner in both positions, and the simple Philidor Position is eventually reached in both. Is there a way to find the longest win where the bishop is NOT the same color as the corner? So far, the longest win I've found is 7K/1r6/8/R2bk3/8/8/8/8 b - - 0 1 where the simple Lolli Position is eventually reached. I've never found a position where both the Philidor and Lolli positions are sub-variations of the same position.

Another long endgame with a similar bishop problem is KBN vs. KN, because the longest wins will be completely different depending on the color of the bishop compared to the corner that the defender's king is near.