A banzai charge is the term used by the Allied forces to refer to Japanese human wave attacks and swarming mounted by infantry units. This term came from the Japanese cry "'Ten thousand years#Japan, shortened to banzai, specifically referring to a tactic used by Japanese soldiers during the Pacific War.
Origin
The banzai charge is considered to be one method of gyokusai, a suicide attack, or suicide before being captured by the enemy such as seppuku. The origin of the term is a classical Chinese phrase in the 7th-century Book of Northern Qi, which states "丈夫玉碎恥甎全", "A true man would be the shattered jewel, ashamed to be the intact tile." Among the rules there existed a code of honor that was later used by Japanese military governments. With the revolutionary change in the Meiji Restoration and frequent wars against China and Russia, the militarist government of Japan adopted the concepts of Bushido to condition the country's population to be ideologically obedient to the emperor. Impressed with how samurai were trained to commit suicide when a great humiliation was about to befall them, the government educated troops that it was a greater humiliation to surrender to the enemy than to die. The suicide of Saigō Takamori, the leader of old samurai during the Meiji Restoration, also inspired the nation to idealize and romanticize death in battle and to consider suicide an honorable final action. During the Siege of Port Arthur human wave attacks were conducted on Russian artillery and machine guns by the Japanese which ended up becoming suicidal. Since the Japanese suffered massive casualties in the attacks, one description of the aftermath was that " thick, unbroken mass of corpses covered the cold earth like a coverlet". In the 1930s, the Japanese found this type of attack to be effective in China. It became an accepted military tactic in the Japanese army where numerically weaker Japanese forces, using their superior training and bayonets, were able to defeat larger Chinese forces. The Japanese here did not face massed automatic weapons but rather the bolt action rifle of the Chinese, which could not fire as rapidly as a machine gun.
During the war period, the Japanese militarist government disseminated propaganda that romanticized suicide attacks, using one of the virtues of Bushido as the basis for the campaign. The Japanese government presented war as purifying, with death defined as a duty. By the end of 1944, the government announced the last protocol, unofficially named ichioku gyokusai, implying the will of sacrificing the entire Japanese population of 100 million, if necessary, for the purpose of resisting opposition forces. During the U.S. raid on Makin Island, on August 17, 1942, the U.S. Marine Raiders attacking the island initially spotted and then killed Japanese machine gunners. The Japanese defenders then launched a banzai charge with bayonets and swords, but were stopped by American firepower. The pattern was repeated in further attacks, with similar results. During the Guadalcanal campaign, on August 21, 1942, Colonel Kiyonao Ichiki led 800 soldiers in a direct attack on the American line guarding Henderson Field in the Battle of the Tenaru. After small-scale combat engagement in the jungle, Ichiki's army mounted a banzai charge on the enemy; however, against an organized American defense line, most of the Japanese soldiers were killed and Ichiki subsequently committed suicide. On May 29, 1943, during the Battle of Attu, the beleaguered Japanese soldiers led by Colonel Yasuyo Yamasaki in Attu Island, Alaska, launched a massive banzai charge through American lines near Massacre Bay and were quickly wiped out all night despite intense fighting. At the end of the battle, only 29 remained of the Japanese force that had numbered roughly 2,600, while the Americans lost 549 combatants out of the 15,000. The largest banzai charge of the war took place during the Battle of Saipan. General Yoshitsugu Saitō gathered almost 4,300 Japanese soldiers, walking wounded and some civilians, many unarmed and ordered the charge. On July 7, 1944, it slammed directly into the Army's 1st and 2nd Battalions of the 105th Infantry Regiment, who would lose almost 2,000 men in the 15 hour pitched battle. In the end, U.S. Army and Marine lines would hold, and almost all the Japanese soldiers taking part in the charge would be killed. Banzai charges were always of dubious effectiveness. In the early stages of the Pacific War, a sudden banzai charge might overwhelm small groups of enemy soldiers unprepared for such an attack. However, by the end of the war, a banzai charge's participants suffered horrendous losses while inflicting little damage in return, particularly if launched against an organized defense with strong firepower, such as automatic weapons, machine guns and semi-automatic rifles. At best, they were conducted by groups of the last surviving soldiers when the main battle was already lost, as a last resort or as an alternative to surrender. At worst, they threw away valuable resources in men and arms in suicidal attacks which only hastened defeat. Some Japanese commanders, such as General Tadamichi Kuribayashi, recognized the futility and waste of such attacks and expressly forbade their men from carrying them out. Indeed, the Americans were surprised that the Japanese did not employ banzai charges at the Battle of Iwo Jima.