Having skillfully removed the Minamoto family from ruling circles, the Hojo Regency governed Japan for over a hundred years, during which time Zen became the most influential religion in the land. It was also during this time that Zen played an important role in saving Japan from what was possibly the greatest threat to its survival up to that time: the invasion attempts of Kublai Khan. In 1268 the Great Khan, whose Mongol armies were in the process of sacking China, sent envoys to Japan recommending tribute. The Kyoto court was terrified, but not the Kamakura warriors, who sent the Mongols back empty-handed. The sequence was repeated four years later, although this time the Japanese knew it would mean war. As expected, in 1274 an invasion fleet of Mongols sailed from Korea, but after inconclusive fighting on a southern beachhead of Kyushu, a timely storm blew the invaders out to sea and inflicted enough losses to derail the project. The Japanese had, however, learned a sobering lesson about their military preparedness. In the century of internal peace between the Gempei War and the Mongol landing, Japanese fighting men had let their skills atrophy. Not only were their formalized ideas about honorable hand-to-hand combat totally inappropriate to the tight formations and powerful crossbows of the Asian armies (a _samurai_ would ride out, announce his lineage, and immediately be cut down by a volley of Mongol arrows), the Japanese warriors had lost much of their moral fiber. To correct both these faults the Zen monks who served as advisers to the Hojo insisted that military training, particularly archery and swordsmanship, be formalized, using the techniques of Zen discipline. A system of training was hastily begun in which the _samurai_ were conditioned psychologically as well as physically for battle. It proved so successful that it became a permanent part of Japanese martial tactics. The Zen training was urgent, for all of Japan knew that the Mongols would be back in strength. One of the Mongols' major weapons had been the fear they inspired in those they approached, but fear of death is the last concern of a _samurai _whose mind has been disciplined by Zen exercises. Thus the Mongols were robbed of their most potent offensive weapon, a point driven home when a group of Mongol envoys appearing after the first invasion to proffer terms were summarily beheaded.