Re: JoshSpecht - Lesson: Queen vs. Pawn on the 7th rank [6:1
I just got a really interesting variant on this in the endgame simulator.
The starting position was:
White: K a4, Q f5
Black: K a2, P b2
Now, I know that this position would just about never happen, but it is interesting how it plays out.
Given the position of the White King, the only move that prevents Black from promoting instantly is a Queen move to the second rank:
(Or: 1. Qf2, which produces an identical position after the fourth move, with all the other intermediate moves being the same.)
This leaves only one legal move for Black:
1. ... Ka1
Then, there is only one good move for White. It actually turns out to be a very good move. All Queen moves are obviously bad, and four of the five King moves make handing a tempo to Black inevitable, so this leaves:
But then I was more than a little surprised by Black's response:
2. ... b1=N+
This then plays out:
3. Kb3 Nd2+
4. Qxd2 Kb1
(or 5. Qd1#)
Now, I was all ready to say that Crafty had blundered (or at least acquired a sense of humour) with 2. ... b1=N+. So I got some real chess pieces out and played out the obvious version:
2. ... b1=Q
3. Qc3+ Qb2+
So well done, Crafty, for delaying checkmate by one move! And I'm seriously impressed that it has been programmed to be able to underpromote, seeing how rare it is that underpromotion achieves anything ( http://www.xs4all.nl/~timkr/chess2/minor.htm
). Of course, a human would probably resign after 2. Ka3.
For the interminably curious, underpromotion to Rook works the same as promotion to Queen here; underpromotion to Bishop is even worse, resulting in 3. Qb2#; and the King move is obviously silly: 2. ... Kb1, 3. Qxb2#.
In the 1. Qf1 line, Crafty still underpromotes to Knight. Why promotion to Queen doesn't work in this line is a little less obvious (or at least it was to me): 1. Qf2 Ka1, 2. Ka3 b1=Q, 3. Qd4+ Qb2+, 4. Qxb2#. I found it all too easy to nonchalantly play 3. Qd2 and end up drawing.
Anyway, that was probably one of the most practically irrelevant endgame simulator positions I have ever played, but it was strange in such a beautiful way that it made me smile. And I'm sure I've learnt something from it, even if it is just "don't play nonchalant moves in endgames".