Why did Japan choose to keep the emperor and give up the army? Isn't the army more practical and powerful?

Because the actual leader during World War II was the emperor, not the government, which is different from now. During World War II, the emperor had great power, and he could replace anyone in the government and army. In other words, if the United States wants Japan to surrender, in the final analysis, it still has to negotiate with the emperor. . At the beginning, the United States demanded to depose the emperor, which was also the fundamental reason why Japan still advocated resistance to the end despite losing ground. After all, if the emperor is deposed, he will definitely be a war criminal, will never live, and will definitely not agree. . Later, when Japan's morale was further hit after the atomic bomb was destroyed, it also realized the influence of the emperor and agreed not to depose the emperor in exchange for Japan's surrender.

Moreover, it is not something that Japan can keep. It was absolutely impossible for Japan to keep its troops at that time. Even if it overthrew the emperor by itself, the United States can't let you keep the army after you surrender, because the United States has long planned to cultivate Japan into a base camp in East Asia, nominally to prevent the resurrection of militarism and prohibit Japan from having an army. But in fact, it is to implement Japan-US security regulations, let the United States enter Japan, and further control Japan.