The kanji that we Japanese use today have a long history of change. The origin of Kanji is unknown, but the oldest forms of Kanji that can be seen today are characters carved on tortoise shells and animal bones during the Shang Dynasty, and are said to be over 3,000 years old. This is called oracle bone script.
Next, from the Shang to the Zhou and Spring and Autumn periods, characters were engraved on metal vessels. This is called Jinbun or Zhongdingbun, and is extremely pictorial in form.
Later, as time passed, Qin Shihuang appeared, and he not only unified the country, but also attempted to unify the written language. This is the decorative "Ten-sho"(Stamp font) engraved on bells and other objects. In the Han Dynasty, for practical reasons, a simplified script called "Rei-sho was created, omitting the dots.
Later, during the Nanbokucho period, "Kai-sho" was born, and at the same time Gyo-sho and Cursive calligraphy were also created, and the font of Kanji became fixed.
This script is the origin of the current Kanji culture of Japanese calligraphy.