This is a misconception that Japanese soldiers would sacrifice themselves 'at the drop of a hat'.

Japanese soldiers held on to life as dearly as any American soldier. Throughout the conflicts of the time period, when Japanese soldiers were well supplied, well armed, and in superior positions, they never threw away men on 'brave' charges, nor did they ignore the severe consequences of draining lots of manpower this way.

Even a cursory glance through the diaries of any group of Japanese soldiers shows that the Japanese soldiers valued their lives as much as any American.

So the question is why were these soldiers so SEEMINGLY willing to die to observers?

Well, let's look at when these kinds of 'suicidal' attacks occurred and how and when they folded into Japanese military doctrine.

The infamous banzai charges were nearly always conducted by men who were isolated, low on food, ammo, and supplies, stricken with casualties and disease.

Also, suicidal banzai charges that were usually committed against orders should be differentiated from organized bayonet charges, which were used to great effect in the early stages of the war, particularly in China, Indochina, and Malaysia.

I wrote a massive post about it here 2 years back and would love to answer any questions you have or clarify things in my old post!

A lot of the early Banzai charges were very wasteful in terms of Japanese manpower. Also, it is one thing to indoctrinate people to be willing to die for a cause and a different thing to get that to motivate them. In many cases Japanese soldiers committed suicide rather than continue to fight. If you are going into a fight completely certain that you die in that fight then when/how exactly you die becomes less important so there is no real incentive to fight smart. The honor comes in the death.