In the old days, we used to have frequent wars in Japan.
The original armor was designed for the needs of the late Heian period, as well as the Muromachi and Sengoku periods when warriors were fighting with arrows. Then it changed, as swords and spears became the weapons of choice.
In this period, the samurai who respected the achievements in war considered it was considered cool to stand while fighting. So they began to attach unique designs to the front part of their helmets.
Some examples include a centipede, a large kanji for “love”, a deer horn, a Japanese paper decoration, leather or animal hair, and so on. They say many designs were quite wild, reflecting the warriors’ temper in that period.
Because the Edo period had much less war, the industrial art technique was developed further, and they made even more diverse and eccentric helmets.