Not just for the NPB, the Japan Baseball Hall of Fame honors important names in all aspects of Japan's baseball history. Start by entering the glass doors, paying your admission, and heading downstairs.
The Hall of Fame members include NPB stars, team owners, college and high school stars, and managers from teams at all levels. Really, anyone associated with any field related to Japanese baseball can be found in the museum, which makes collecting cards of all the members impossible. I spent a lot of time photographing each plaque because some members don't even have readily available photos online.
Heading back upstairs, you can find a small museum shop (more of a display case with goods for sale at the entrance) which has pins, a few books, official baseballs, and chopsticks made from broken bats.
Overall, the museum is smaller and less exciting than the Cooperstown counterpart, but for a smaller country with fewer teams, it certainly serves its purpose.
The museum is open from 10 AM to 6 PM, closing at 5 PM November through February. Admission is 500 yen, but a 100 yen discount coupon can be found on the website. The entrance is to the right of Gate 21 of Tokyo Dome, a short walk from Suidobashi, Kasuga, and Korakuen Stations.