Yakyuu Kakutou League-Man

The title of this game translates from Japanese as 'Baseball Hand-to-Hand Fighting League-Man'.

This game is known in US as "Ninja Baseball BatMan".

Irem America opened its U.S. office in 1988 in Redmond, Washington, headed up by Frank Ballouz (founder of FABTEK, a thriving video kit company and former North American publisher of several arcades by Seibu Kaihatsu and TAD Corp.) and National Sales Manager Drew Maniscalco. During this time, Drew created the Ninja Baseball Bat Man video game concept (including the English title, plot and characters) and licensed it to Irem America in 1991. To illustrate the characters' sketches, Drew hired Gottlieb's well-known pinball artist, Gordon Morison.

Drew's concept came up after he read the top grossing films during its time in a USA Today newspaper. One was Teenage Mutant Ninja Turtles, the other was one of the Batman films (possibly Batman Returns). After that, he started creating his own superhero influenced by what he saw in the USA Today newspaper. During the development of his concept, he liked the word NINJA, because of it sounding mysterious to him. He gave the protagonists baseball bats and baseballs as their main weapons, as well as dressing them in baseball uniforms, because both the sport baseball was quite popular nationally in Japan, and Drew is also a baseball fan. Drew thought the baseball bat idea was also probably an influence from the 1973 film Walking Tall. The word MAN in the title comes from Joe Don Baker who starred in the film, while he was a man. He later created the concept for the other characters such as enemies. To illustrate the characters' sketches, Drew hired Gottlieb's well-known pinball artist, Gordon Morison.

Drew's original gameplay ideas for the video game was for a 1-player, adventure-based, platform game similar to Nintendo's "Super Mario Bros.". However, due to the very successful game sales of several 4-player games (most of them being beat 'em ups), Drew added 3-players in an effort to compete with the 4-player games. While the title and characters were Drew's concept, Irem Japan programmed the arcade game, and modified the look of its prototype. Drew did not mind it being different, as he was thrilled about it being programmed by them.

During the development of the 2-player platform version, the two main characters were named Willie and Mickey, named after Drew's two favorite baseball players of his childhood, Willie Mays and Mickey Mantle.

During the development of the 4-player beat 'em up version, the prototype names of the four main characters were Captain Jeff (red), Nunchaks Sugar (green), Hammer' Eddy (yellow) and Naginata Jimmy (blue). Drew later came up with the final names of the four protagonists that are currently used in the finished version today, which the names are references to the four baseball stars during the arcade game's release: Jose Canseco (red), Ryne Sandberg (green), Roger Clemens (yellow) and Darryl Strawberry (blue). In Japan, they were named after their colors.

A year after its concept was created and a year before it was released, despite it being interesting in his opinion, Drew left the company in 1992 and moved to Data East USA. Because of that, he was unable to market nor manage any other input related to the game.

An ad for "Mahou Keibitai Ganhooki" appears on the first stage, another Irem game.