A. -16 & #1 Proca retractor composer: Joaquim Crusats, Die Schwalbe 330 12/2024 (model by S.Nikhto)
White and black take turns retracting strikes (white begins) and after white retracts 16 strikes, white makes ahead checkmate in 1 transfer.
B. -46 & #1 Proca retractor composer: Joaquim Crusats, Die Schwalbe 330 12/2024 (model by S.Nikhto)
White and black take turns retracting strikes (white begins) and after white retracts 46 strikes, white makes ahead checkmate in 1 transfer.
In assist retractors, the gamers act cooperatively. However in a Proca retractor, the play is adversarial. Black chooses his retractions: in order to forestall white from finishing the duty.
The strikes are returned one after the other (white retracts a transfer, black retracts a transfer, in whole, white retracts 16 strikes, black retracts 15), black and white don’t cooperate, and when selecting which transfer to return, black will select strikes that forestall white from finishing the duty in a given variety of strikes. It is like a daily recreation of chess, however we’re not shifting ahead, we’re shifting backward. After the retraction of transfer 16, white instantly strikes ahead with checkmate. (in puzzle A, in puzzle B equally, however there are 46 strikes)
The rule is that the returned strikes mustn’t result in the illegality of the place. If Black can ever make a ahead transfer that’s checkmate, then they’re thought of to win: in order that’s one thing else White should keep away from.
UPD. There was a typo because of technical causes. On e1 bQ, not bB.
For reference: the unique activity
A. -16 & #1 Proca retractor
composer: Joaquim Crusats, Die Schwalbe 330 12/2024
B. -46 & #1 Proca retractor
composer: Joaquim Crusats, Die Schwalbe 330 12/2024 (Ka7 on a5)**
Sadly, there have been many aspect options within the authentic:
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- Bc4-d3 Bd3-e2 2. Re2-e3 …
-
- Bc4xPd3 d4-d3 2. Rd3-e3 …
in each circumstances, it’s sufficient for white to return solely 9 strikes after which checkmate
Plus, there’s a catch for B (lowering the answer by about 12 strikes):
- Cc4xPd3 d4-d3 2. Cd3xPc4 c5-c4 …
The proposed correction eliminates the opportunity of liberating the e3 sq. for the knight f1 and the opportunity of reviving pawns on the vertical d on the primary transfer of the choice. On the identical time, the writer’s determination stays utterly unchanged.
For possibility A, I am a hundred percent certain. Possibility B has not been absolutely examined. Maybe, by joint efforts, it will likely be doable to approve it. Nicely, or refute it.
