Consequent Series Mover

Glossary

Series-movers ask for one side to play a long series of consecutive moves. In series-mates, White plays the series and try to mate Black at the end of the series. In series-helpmates, Black plays the series and try to reach a final position where White may mate in one. In series-selfmates, White plays the series and try to reach a final position where Black must mate him in one.

During the series, it is not allowed to walk into check, or to check the opponent before the last move of the series, when he can answer the check.

Consequent series-movers are series-movers where, at every moment during the series, the intermediary position must be legal as if we were in an orthodox game. The previous rules about walking into check still apply, but additionally it is not possible to enter positions with no retro-analytically "legal past". For retro-analytical purposes, all intermediary positions are evaluated independently.

Michel Caillaud
diagrammes, 1979
Ded. G. Yacoubian

[r7/4k3/1p1b4/3p4/3p4/1Pp3pp/1PP3Pp/7K]

5+10. shc#15 (Consequent Series-Helpmate in 15 moves)

The try 1. Ra3 2. Rxb3?? 3. Rb5 4. Bb4 5-7. Kc4 8. Rc5 9. b5 b3# fails because Wh. has no last move after 2. Rxb3.

The solution is to first capture the wh. Pg2 so that the White King has -1. Kg2-h1 as a possible last move. 1. Rf8 2. Rf2 3. Rxg2!! 4. Rf2 5. Rf8 6. Ra8 and we go on as in the try.

Castling and en-passant capture

Castling and en-passant captures are allowed in consequent series-movers, using the usual conventions. The one point specific to consequent series-movers is that the legality conditions are evaluated in the intermediary position independently of the earlier moves of the series.

C. Wiedenhoff
Rex Multiplex 15-16, 1985

[B5kr/R6p/P7/8/8/8/7B/7K]

5+3. shc#8 (Consequent Series-Helpmate in 8 moves)

After 1. Kf8 2. Ke8 we reach a position where, if it was the starting point of a problem, Bl. could castle according to the usual conventions for castling rights.

In consequent series-movers, the intermediary positions are evaluated independently, so that we may go on as if we were in the starting position and play 3. O-O!!. The fact that we have just moved the bl. King from g8 is explicitly disregarded in consequent series-movers.

Now 4. Rxa8 5. Kf8 6. Ke8 7. O-O-O!! is legal according to the consequent series-mover logic. We conclude with 8. Rd7 Ra8#.

Acknowledgments: most material for this page is extracted from [Cai85b].