In Japan, high school baseball (koko yakyu) generally refers to the two annual baseball tournaments played by high schools nationwide culminating at a final showdown at Hanshin Koshien Stadium in Nishinomiya, Japan. They are organized by the Japan High School Baseball Federation in association with Mainichi Shimbun for the National High School Baseball Invitational Tournament in the spring (also known as "Spring Koshien") and Asahi Shimbun for the National High School Baseball Championship in the summer (also known as "Summer Koshien").
These nationwide tournaments enjoy widespread popularity similar to that of NCAA March Madness in the United States, arguably equal to or greater than professional baseball. Qualifying tournaments are often televised locally and each game of the final stage at Kôshien is televised nationally on NHK. The tournaments have become a national tradition, and large numbers of frenzied students and parents travel from hometowns to cheer for their local team. It is a common sight to see players walking off the field in tears after being eliminated from the tournament by a loss.
The star players of the championship team achieve a degree of celebrity status. For the players, playing at Kôshien is the door to playing at the professional level. Due to the recruiting practices of Japanese high schools, top prospects often play on strong teams that are able to reach the final tournament at Koshien. Several professional baseball players first made their mark at Kôshien, including Bando Eiji, Oh Sadaharu, Ota Koji, Egawa Suguru, Kuwata Masumi, Matsui Hideki, Matsuzaka Daisuke, Yu Darvish and Tanaka Masahiro.