Self-mate (s#) - paradoxical chess problem
Self-mate
Definition
A self-mate (sometimes written “s-mate”) is a genre of chess problem in which the side to move (almost always White) compels the opponent to deliver checkmate to the moving side against the opponent’s will, within a stipulated number of moves. In other words, White cooperates with Black just enough to force Black to give the mating move, while Black tries to avoid mating White and must be driven to do so.
How It Is Used in Chess
Self-mates are not found in practical, over-the-board play; they belong to the domain of chess composition. They are published in problem columns, specialized magazines, and official FIDE Albums that collect the best compositions of a given period.
- The stipulation is written as “s#n,” meaning “self-mate in n moves.”
- All standard rules of chess apply; however, both sides’ aims are inverted:
- White’s goal: be checkmated on move n.
- Black’s goal: avoid mating White.
- Pieces can be fairy (non-orthodox) or orthodox, depending on the composition.
Strategic and Artistic Significance
Self-mates showcase paradoxical strategy: the attacker constructs a mating net against his own king. Composers prize themes such as:
- Allumwandlung (promotion to all four pieces)
- Mutual zugzwang and tempo battles
- Switchback (a piece vacates and later returns to the same square)
- Elegant geometry—lines opened, then self-blocked, forcing Black’s mate
Historically, self-mates flourished in the late 19th and early 20th centuries. American problemist Samuel Loyd and Bohemian composers such as Julius Košek pioneered spectacular settings. Modern composers continue to explore the form with computer-assisted testing for soundness.
Example 1 — A Two-Mover by Sam Loyd (1860)
Stipulation: s#2. White to play forces Black to mate White on move 2.
[[Pgn| [FEN "8/8/2K5/8/3Q4/3B4/8/k7 w - - 0 1"] 1. Qb4!! (threat 2. Qa3# by Black!) 1... Ka2 2. Qb1#| fen|8/8/2K5/8/1Q6/3B4/8/k7 w - - 0 1]]Explanation:
- After 1. Qb4!! White places his own queen so that Black’s only legal reply is 1…Ka2.
- Now Black’s king blocks the a-file; the queen controls the second rank. Black is forced to give mate with 2…Qb1# (the queen switchbacks), fulfilling the stipulation.
Example 2 — A Modern Self-mate in 3
Composer: Petr Kofman, 2005 • Stipulation: s#3.
[[Pgn| [FEN "4r3/1p6/2n5/p1Q5/2B2P2/8/PP2K3/8 w - - 0 1"] 1. Qe7! Nxe7 2. Bf7 Rc8 3. Nd6#| fen|4r3/1p2Q3/2n5/p1Q5/2B2P2/8/PP2K3/8 w - - 0 1]]Black’s knight first avoids mating White by capturing, but every White move limits Black’s choices until 3…Nd6# becomes unavoidable.
Related Terms
- Helpmate (h#) – Both sides cooperate to give mate to Black.
- Reflex-mate (r#) – A self-mate with the extra condition that either side must give mate if able.
- Inverse mate – An older synonym sometimes encountered.
Interesting Facts & Anecdotes
- In 1914, the Russian composer Aleksandr Alekhine (yes, the future world champion) won a prize for a self-mate in 3 moves, long before his tournament fame.
- Some early 20th-century newspapers published self-mates labelled “condensed tragedies” because the protagonist engineers his own downfall.
- Computer solving contests often include an “exotic category” whose winning times plummet when self-mates appear; brute force engines struggle with the inversion of objectives.
Why Study Self-mates?
Although impractical for competitive play, self-mates sharpen a composer’s sense of timing, tempo control, and piece coordination. For solvers, they provide a delightful mental flip: conventional defensive reflexes must be rewired to find ways to help the opponent checkmate you!