My young colleague Leif enjoys endgames, and has an endless curiosity about unbalanced endgames. So he asks:
can you win with three pawns against a Bishop?
how about a Knight?
what about two Knights?
A pattern we kept running into was:
united pawns on their start squares don’t win against a piece (a)
united and *advanced* pawns win against a piece (b)
but
there are some special cases where the side with the piece can set up a blockade or fortressagainst advanced pawns (c)
So it’s less like that famous Internet question
who would win in a fight between a lion and a bear?
but
who would win in a fight between a fox and a hedgehog?
Anyhow, we ended up looking at a few fortresses, some I knew, some I had
to look up, and some I found out more about.
There are cases where a lone King can be a ‘toad in a stone’, wedged in and impossible to shift.
The Japanese might say a ‘bear in the hole’… Notice that these cases
are all in the corner of the board. Edges and corners are friends of the defending side.
With a pawn to help, the King can resist near a corner without being in
it:
It’s perfectly possible to draw when you are the exchange behind, if you
can keep out the enemy King. That’s another theme: keeping out the
attacking King.
The mighty Queen can be kept at bay, as long as the attacking King can’t
get in:
We played around with variations on that last fortress, and then looked
it up. It’s sort of interesting: if the pawn is advanced, the Queen can
get behind your defences and you lose, but if the pawn is advanced and
on the edge, you are able to hold again.
To break down the defence, you have to use zugzwang to make the Rook
abandon the King.
The same ideas occur in the ‘simple’ Q vs R endgame, which six-times US
champion GM Walter Browne failed to win against a computer in the 1970s,
before looking up the right technique… Try it against your own
computer!
Fortresses in practice
Here’s one from a game I had a year or two ago: I got through, but I
think I shouldn’t have been allowed to.
A couple of well-known ones at GM level: a great swindle by Zsuzsa
Polgar:
Another sad tale of the wrong Rook’s Pawn!
And a spectacular save:
P.S. Foxes are said to eat hedgehogs by rolling them into water, when the hedgehog will unroll to swim, and loses its life.