Many of the Japanese civilians would kill themselves to prevent their capture by American troops. On Okinawa ans Saipan for example:
http://www.iht.com/articles/2005/06/20/news/oki.php
ITOMAN, Okinawa Clutching a hand grenade issued by the Japanese Imperial Army and driven by tales of what U.S. soldiers would do with a pretty young woman, Sumie Oshiro recalled, she fled into the forests of Okinawa during the World War II battle known here as the "typhoon of steel."
"At one place, we sat together and hit the grenade on the ground, but it did not explode," she said last week of her flight with friends after Japanese soldiers told them to kill themselves rather than be taken captive.
"We tried to kill ourselves many times, trying to explode the grenade we were given from the Japanese Army," she said.
The three-month battle for Okinawa took more than 200,000 lives - 12,520 Americans, 94,136 Japanese soldiers and 94,000 Okinawan civilians, about one-quarter of the prewar population.
http://www.pbs.org/wgbh/amex/pacific/pe ... iroma.html
Mass Suicides
The civilian population on Saipan numbered close to 30,000. Twenty-two thousand were Japanese -- though most came from the prefecture of Okinawa and were ethnically distinct from other Japanese. The rest consisted of Korean slave laborers and the original inhabitants of the island -- the Carolinians and the Chamorro. As the battle of Saipan reached its final days, Japanese soldiers and panicked civilians made their way north to Marpi Point. Here, despite repeated calls by the U.S. military to surrender, civilians chose death by jumping off cliffs or drowning themselves in the sea. They had been led to believe that surrender would mean murder, rape and torture at the hands of U.S. forces.
http://www.globalsecurity.org/military/ ... battle.htm