Coined in the R.A.F. in 1940 from German Sitz, from sitzen, to sit + Krieg, war, modeled after and parodying blitzkrieg -- and thereby hangs a tale. As you may remember from the history of World War II, in the roughly six-month period after the declarations of war between Germany, France, Great Britain, et alia, not much happened on the Western Front. Germany mopped up Poland in a blitzkrieg, "lightning war", (re)took the Saar valley, and invaded Denmark and Norway, but avoided France and the Netherlands for the moment. It turned into a waiting game for the Western Allies, and the expected bolt never struck -- a "sitting war" waiting for something to happen. Eventually Hitler attacked, though, and the Allies found that the war was not phoney after all.
The longest match of the tournament was a veritable sitzkrieg, lasting 105 moves and three and a half hours only to end in a draw.
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