[Rummyfan]

"The strength under my command is now about four hundred. Tanks are attacking us. The enemy suggested we surrender through a loudspeaker, but our officers and men just laughed and paid no attention." Kuribayashi was likely to be killed on that same day, but his body was never found.

Were they insanely brave or simply insane? I don't know.

[SunkenCiv]

There are four ways to go for the old-school Asian warriors:

1 — go to battle and win
2 — die in battle
3 — go to battle, realize you’re beaten, and run for it (still honorable, but you don’t brag about it)
4 — dishonorable options are surrender and capture

about 99% of Japanese on Iwo died there (and good riddance).

Regarding option #3 (and #2), Chinese military thinker Sun Tsu noted that it was necessary to always leave the enemy an avenue of escape, otherwise the adversaries would fight to the death.

[fso301]

Were they insanely brave or simply insane?

Pagan fanatics is what they were.

[Alas Babylon!]

Surrender in battle was considered a terrible dishonor. Worse than rape or murder.