Bat Kid 

Nagai (aka Bat-kun), is a junior high school student, who joins the baseball team as a substitute. Now, he aims to become a regular player in team. Note: It is considered to be the first baseball manga in Japan. It was initially cancelled due to the author passing away in May 1949, the last chapter being published in the March 1949 issue, but was finished by Eiichi Fukui.