Problems of the type for which the author is infamous are limited in number, for they demand a combination of qualities not often found together. They should be problems rather than puzzles, instructive rather than baffling, presenting situations that arise in everyday play. They should be short and snappy, and anserable by a concise statement, preferably early in the game; for if delayed too long, variations in defense may lead to complications that destroy the problem. Above all, they should offer two schemes of play, one that may be plausible at first sight, and another that a deeper analysis proves to be the correct procedure. And if there is a big swing between the results of good technique and bad technique, so much the better, for there is nothing like punishment to emphasize a lesson for man and beast.