World Record

Of course the chess position itself must be "legal", i.e. it must be possible to reach it from the starting position.

The record for such a sequence is 18 plies (9 moves by each side).

It is unbeaten since I published it in 1976.

(See problem 493 in Journal of Recreational Mathematics, 9:2, 1975-76, pp130-131,
solution of this problem in a later issue).

So here is the chess position (can you improve on it?) :

The 9 forced moves are:

** White Black**

1. QxQ+ RxQ+

2. BxR+ RxB+

3. QxR+ RxQ+

4. QxR+ RxQ+

5. QxR+ RxQ+

6. QxR+ RxQ+

7. RxR Pg4+

8. RxP+ PxR+

9. KxP KxR

Click here to DOWNLOAD the Zillions ".zsg" file to play it out.

Note that three of the eighteen plies do **not **involve a check.

Can you prove that after the nineth move, White has a mate in six moves?

(Hence the position above is a "mate in 15").

Can you find a sequence of moves that leads from the starting position to
the position given above?

What is the sequence with the least number of moves?