Armand Lapierre

Armand Lapierre (05-06-1899 - 24-01-1968) French chess composer

Armand Lapierre was the president of the French Problemists Association. He was presented in an article published in Thèmes 64 25/1962 pages 386-387. He is renowned for this particularly clear presentation of mutually exclusive castlings.

Die Schwalbe (Germain magazine of chess problems) reports (Issue 289, February 2018):

Armand Lapierre (5.6.1899-24.1.1968) composed only around 50 problems, but was productive in all genres. He was also chairman of the French problemist community, represented France as a delegate to the PCCC and organised the 12th Congress of the PCCC in France. However, he did not live to see this meeting in Arcachon, as he died a few months earlier, 50 years ago. As an example of his work, an easy-to-understand "retro for all" is shown here: The double castling position catches the eye; if White plays Ta1 to d1, Black can avert the mate threatening on d8 by castling - provided it is still legal. This is always the case when the opposite cannot be proven. After 1.Tad1? castling is possible because the wTd4 could be the original Th1, which the wK, which later returned to e1, could have let out. But if we assume that White is still allowed to castle (in which case he must do so in order to eliminate Black's castling, i.e. 1.0-0-0!), then the Td4 inevitably proves to be a converting rook, since the previously unmoved Ke1 meant that the Th1 could never leave its corner (except by being captured). The rook on d4 therefore originated on the 8th rank and could only have left it via d8, f8 or h8. Each of these possibilities means that either the sK or the sTh8 must have moved, meaning that black castling is no longer allowed.

Source: wikipedia.de