The Japanese commanders Ushijima Mitsuru and Cho Isamu both committed suicide after losing the battle of Okinawa. This was far from the only example of suicide among the Japanese high command once it became apparent that the war could not be won. Most notably, war minister Anami Korechika commited seppuku following an argument with the emperor in August 1945, in which he advocated for continuing the war despite the emperor's support for surrender. Following his suicide, a number of junior officers attempted a coup against the emperor, aiming to continue the war. Non-traditional methods of suicide were also common among the high command at that time, with General Tanaka Shizuichi commuting suicide by shooting himself in the heart ten days later. Ironically, General Tanaka had been opposed to the attack on Pearl Harbor in the first place, but still insisted on fighting to the bitter end (though he was instrumental in stopping the attempted coup,) and felt personally responsible for the damage dealt to Tokyo following the American firebombing of the city. He had tried to resign his command 3 times before his suicide, each time being denied.

Just to give some context

Its important to note that WW2 was a return to this traditional ways, at an even wider unprecedented scale then ever seen before. In the early 20th century Japan was humiliated in battle numerous times. This was after the emperor dissolved the samurai class and instilled a more traditional western military to protect the country. Though the samurai class still ran the military and thus held a lot of sway and power. The lost many battles being run by the civilian government. In these days not as many instances of seppuku took place as you would think. The military leaders felt their country had become soft and weak, that Japan which had stood firm for thousands of years would begin to crumble. Finally the military usurped the throne assassinating the prime minister in 1932, basically cutting off the head of the civilian government and returning it to a military ran one. Through the 30's and 40's military recruiters were placed in all schools throughout Japan. Thus culturally they turned to a society in which all Japanese began to exhibit these classical samurai teachings. It was a return to Bushido(Samurai teachings), including seppuku. So in WW2 we see the culmination of this cultural shift. It was fought by an army of soldiers who had since childhood been taught these things, and thus the instances of kamikazi and suicide etc where much more pronounced than they had been ever before.