Solution

**Luigi Ceriani**

La Genesi delle Posizioni,
1961

Ded. D. E. Cohen & F. R. Oliver

12+12. Vertical cylinder.
Where is the h-a border?

What was the 1st move of the black QB?

**Solution:** Here we write a' to h' to denote the columns
*as they appear on the diagram*.

W captured all four missing black men with a'2xb'3 and h'2xg'3xf'4xe'5.

The black K could only enter the south cage through d'3, when the
white pawns were on c'3, d'2 and e'3. Thus Bc1 really is a promoted
B while the original black B on black squares (KB **or**
QB) did leave his initial square, which really was f'8 or h'8, and got
captured by the h' white P.

Three of the four black captures are b'7xa'6, g'7xh'6 and f'3xe'2 to reach the promotion square e'1.

The only way to unlock the south cage is to take back **Rg'1-e'1+,
Ke'1xBe'2 and Bf'1-e'2+**, explaining the fourth capture by black.
Thus the white B on black squares has been captured by a black P (on
h'6), so that its home square could not have been c'1 or e'1 inside
the south cage. It was a'1 or g'1.

Assuming this home square was g'1, we get g'8 as the home square of the black B on white squares, so that the home square of the other black B is b'8 or d'8, from which it could not have participated in the required captures. Thus the home square really was a'1.

We deduce that the black B's are from a'8 and f'8, and that the h-a border really is the c'-d' line. The first move of the black QB was Bf'8-g'7 (i.e. Bc8-d7) and not Bc'8-b'7 as it would appear at first sight.