The Gempei War was one of the most important conflicts in Japanese history, marking the point at which power shifted from the Imperial Court to the samurai and the Shogun. The war was the final clash between two powerful clans, the Minamoto and the Taira, and followed a series of shorter conflicts in which the Taira had been victorious. Despite being the dominant power in Japan, they had chosen to rule through the institutions of the Imperial Court, and the Emperor and a number of retired Emperors had retained a great deal of influence. A handful of Minamoto leaders had survived the previous wars, and in 1180 they took advantage of an unpopular attempt by the Taira to influence the Imperial succession and rebelled. After the Minamoto victory Minamoto Yoritomo took power, and eventually reorganised the government of Japan, becoming the first Shogun.
Shorter accounts of this war can be somewhat confusing. Several different commanders played key roles on both sides, taking part in a series of semi-related campaigns, and many accounts don't correctly link the battles to the campaigns, or explain the relationship between the various commanders.
Here we get a much more coherent account of the conflict. The relationship between the various commanders on both sides are made clear, and the battles organised into their various campaigns. The text is supported by clear maps, including some useful ones of the key area around Kyoto. There is also an impressive collection of medieval Japanese illuminations, which give a good visual impression of the period. Unsurprisingly Turnbull is also very strong on the nature of Japanese warfare in this period, so he is able to place the original accounts of this war in context.
This is an excellent history of this important Japanese conflict, certainly the best that I've read, and probably about the best you'll currently find in English.
Author: Stephen Turnbull