K. Fabel and W. Keym
Basler Nachrichten, 1967
13+3. Problem without words
All 13 missing Bl. units have been captured by the Wh. pawns b2, c2, d2, e2 & f2 going eastward from the b-file to the g-file. wPa2 and wPh2 did not change column. So that bPh3 came from the g-file with one capture (one wN), and the original bPh7 also used one capture (the other wN) to reach the g-file. In order to get captured, both bPa7 and bPb7 had to promote so that either the WPa2 was captured on the a-file, or it was promoted on a8 after Black captured axb and promoted his a and b Ps on b1.
This accounts for all 3 captures by Black, so that Black's only potential last move, -1. e5xf4, is not possible after all. White played last. Last move was necessarily -1. g2-g4 allowing Bl. to avoid retropat by retracting bKg4-h4 wPf2-f3+ bKh4-g4 etc.
Therefore Black has the move (1. Bf2 mate?? is not allowed). Furthermore Black has only one possible legal move: 1 ... f4xg3 ep mate, so that no stipulation is required.