Why did some samurai shave their heads and others not?
Why did samurai have two swords?
Apart from the practical reasons for having a shorter back-up sword, it also helped set them apart from the few non-samurai who were allowed to carry one sword, such as local officials
Why were ancient Japanese swords so long?
They were mainly to be used on horseback
Why did the samurai cut their stomachs rather than their necks or anywhere else to kill themselves?
Like the Chinese, the Japanese believe that the life force (ki, chi in Chinese) is centred on the stomach. Choosing the most painful and least quick way to die also had a bit of macho posturing about it.
Why did harakiri die out?
Somewhere along the way it became a political act as much as a personal one, and as early as when General Nogi commited seppuku after the death of Emperor Meiji, people risked labeling themselves and their families as political fanatics by choosing that extreme method. There is also the practical issue of swords being just as tightly controlled as guns. It must also be remembered that it was only a very small proportion of society that commited (and were allowed to commit) suicide by this method even in the Edo period.
Why did the samurai have their strange haircuts?
Originally it was supposed to make wearing a helmet more secure and comfortable, but once people of lower classes were banned from having their hair oiled up samurai-style it became mainly a status symbol.
Why did the samurai topknot hairstyle disappear?
Apparently the first impetus to cut off the topknot (just the same as the start of wearing Western clothes and eating Western food) came from the Meiji period conscription army that replaced the samurai class. As the topknot would not fit under western-style military hats and helmets it had to be cut off. This was spread slowly to the rest of the country by a government campaign to get rid of all traditions (also spitting, mixed bathing etc) that could make foreigners think the Japanese were “uncivilised” and so extend the amount of time the Japanese had to suffer under the indignity of the same “unequal treaties” on trade that the Japanese had forced on the Koreans.