By the way, I liked a lot the problem of Kostas.
The idea is already realized with 1336. But it is not justified an added condition (Rockagogo) for a single last…
Nice and neat. Would the author manage another white switchback instead of c2-c4-c5, it could be even better.
PWC condition cleverly used to get continuous Berolina effects. Hand of a master!
2 neat under promotions of a neutral pawn moving on to help with helpmate under koeke condition... decent unity too...…
The capturing side
Why not allow the castling on the diagonals also? 🙂
Interesting condition. Who decides decides which piece/pawn shall vanish (when there are more than two)?
Although the non-repeated moves is lost.
Would Pe4->e5 with 2 solutions work?