Elementary School Students Are Invincible in All Worlds

A top college student traveled through time and became a primary school student with a chatting system. From then on, he wandered around the world, picking up girls and fighting monsters, until he discovered that there are not just one or two chess players in the world. The introduction is weak, please read the content, there are fantasy and animation. I'm new to writing, so please bear with me. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.