Excelsior (chess problem)

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"Excelsior" is one of Sam Loyd's most famous chess problems, originally published in London Era in 1861, named after the poem "Excelsior" by Henry Wadsworth Longfellow. Loyd had a friend who was willing to wager that he could always find the piece which delivered the principal mate of a chess problem. Loyd composed this problem as a joke and bet his friend dinner that he could not pick a piece that didn't give mate in the main line (his friend immediately identified the pawn on b2 as being the least likely to deliver mate), and when the problem was published it was with the stipulation that white mates with "the least likely piece or pawn".

[edit] Solution

The solution (in algebraic notation) is as follows:

1. b4

Threatening Rf5 and Rf1 mate. White cannot begin with 1. Rf5 because Black's 1.... Rc5 would pin the rook.

1. ...Rc5+ 2. bxc5

Threatening Rb1 mate.

2. ...a2 3. c6

With the same threat as on move one.

3. ...Bc7

Because both Rd5 and Rf5 are threatened; the alternative moves 3.... Bf6 and 3.... Bg5 would only defend against one or the other.

4. cxb7 any 5. bxa8=Q mate (or bxa8=B mate).

The mate is delivered with the pawn which starts on b2.

Any problem which features a pawn moving from its starting square to promotion in the course of the solution is now said to demonstrate the Excelsior theme. Nowadays it is most usually shown in helpmates and seriesmovers.