An alt-history novel of Operation Coronet, the Allied invasion of Japan set for March 1, 1946, cancelled after Hiroshima and Nagasaki. In this fictional account, the bombs didn't drop and first Operation Olympic, Nov. 1, 1945, had established American forces and air bases on Kyushu, Japan's southern island. This novel covers the invasion of the Japanese homeland itself, with Coronet landing U.S. soldiers and Marines, hundreds of thousands of them, near Tokyo, and the Japanese gathering up thousands of suicide aircraft, mostly obsolete trainers, and millions of soldiers -- and civilians with bamboo spears -- to send into hopeless battle.
Historically, it follows what both sides had planned. Most of the characters are individuals who appear in vignettes, land, sea and air, on both sides, most of them dying in the carnage. Coppel does give the sense of a vast slaughter, and the personalities of the leaders, MacArthur, Nimitz, Truman, Tojo, the Emperor, trying to guide events. Mostly it's a formulaic mix of strategy and people caught up in the spectacle, mostly sketchy characters. There's a romantic love story between an American Army translator and a Japanese woman he had known before the war, but it stretches belief. It's a massive, vivid, but by-the-numbers meatgrinder, an early alt-history (publ. 1983) genre that has had much newer, and better work since.