Ortho Reconstruction


An Ortho-Reconstruction is a maneuver changing the side to move but leaving everything else unchanged. It is sometimes used in forward problems (e.g. to put Bl. in zugzwang). In retros it may be used e.g. to overcome a retro-opposition.

Here is an example:

Luigi Ceriani
La Genesi delle Posizioni, 1961

[3K3N/n1B1PqpP/NPPkrbRB/1pppp1p1/1p5p/8/4P3/8] (solution)

11+13. Release the position


Ortho-Reconstruction as a stipulation

Later, Ortho-Reconstruction has become a stipulation per se. Such problems just ask you to find a way of swapping side to move, using Wh. and Bl. units in cooperation as in helpmates.

Here is an easy example:

Luigi Ceriani
32 Personaggi e 1 Autore, 1955

[k7/Pp2p3/2p1Pp2/1Pp2rp1/N1P1PPP1/2pKRB2/2P1n1p1/5b2] (solution)

12+12. Black to move. Ortho-Reconstruction
(I.e. reach the same position with White to move in the shortest number of moves.)

Note that "leaving everything else unchanged" may involve castling rights, etc.

[Q] What is the length record with legal position?