In mid-1944 Japan mobilized over 500,000 men  and launched a massive operation across China under the code name Operation Ichi-Go, their largest offensive of World War II, with the goal of connecting Japanese-controlled territory in China and French Indochina and capturing airbases in southeastern China where American bombers were based. During this time, many of the newest American-trained Chinese units and supplies were forcibly locked in the Burmese theater under Joseph Stilwell set by terms of the Lend-Lease Agreement. Though Japan suffered about 100,000 casualties, these attacks, the biggest in several years, gained much ground for Japan before Chinese forces stopped the incursions in Guangxi. Despite major tactical victories, the operation overall failed to provide Japan with any significant strategic gains. A great majority of the Chinese forces were able to retreat out of the area, and later come back to attack Japanese positions such as Battle of West Hunan. Japan was not any closer in defeating China after this operation, and the constant defeats the Japanese suffered in the Pacific meant that Japan never got the time and resources needed to achieve final victory over China. Operation Ichi-go created a great sense of social confusion in the areas of China that it affected. Chinese Communist guerrillas were able to exploit this confusion to gain influence and control of greater areas of the countryside in the aftermath of Ichi-go.