Serieshelpmate in thirty three

Solution

1) Serieshelpmate in thirty three

Since there is no immediate mate possible (the king cannot get to a8 for the purpose of setting up d5-d6 mate without capturing the Ra1, thus defeating the purpose!), it is necessary to promote the black d-pawn. To do this Black must remove the Pd5 and all its defenders. The solution runs as follows (the moves given are all by Black):.

1 Kb2
2 Kxa1!
3 Kb2
4 Kxc3!
5 Kxc4
6 Kb5
7 Ka6
8 Kb7
9 Kxa8! (Black must take either the Ba7 or the Na8 to obtain a path to the Bh1)
10 Kb7
11 Kc7
12 Kd6
13 Ke5
14 Kf4
15 Kg3
16 Kh2
17 Kxh1!
18 Kg2
19 Kf3
20 Ke4
21 Kxd5!.

So where is the mate? The astute reader might have noticed that the black king has visited three corners already....

22 Ke6
23 d5
24 d4
25 d3
26 d2
27 d1B!
28 Bc2
29 Bxh7!
30 Kg7
31 Kg8
32 Kh8
33 Bg8

and White mates with Bd4 Mate.

The most striking geometrical effect is the black king's visiting of the four corners of the board. There is also an excelsior - the black pawn making its full-length journey to promotion - as well as an economical final mate (leaving no `extras' on the board).