The trend is all the more remarkable because educational software has always been the videogame version of spinach—good for you, but no second helpings, please. That changed two years ago with the success of Brain Age software, which offers mental drills. Nintendo and other software makers followed with dozens of programs for education, physical training and practical skills. The software is catching on among gamers and nongamers alike—from baby boomers and salarymen to housewives and students. The top-selling programs concentrate on cultural literacy, vocabulary building, math drills and English-language instruction. According to the latest figures from Enterbrain, a Tokyo videogame magazine publisher, as of June educational and training software has sold nearly 20 million copies.

The craze, which so far is limited to Japan, has transformed the Nintendo DS from a videogame player to a daily companion in the school of life—one in seven Japanese people now owns one. “People no longer seem to be buying our software just to play in their free time,” says Fumitaka Nasu at Obunsha, a publisher.

Nintendo, the dominant publisher of educational software, uses videogame tricks to make the programs fun. Some titles rank players at each step of the course; others insert short games between lessons. Hardware is also a factor. The DS has dual screens, recognizes handwriting and responds to voice commands, making it easy for nongamers to control. In English Training, a language-instruction program that’s sold 2.4 million copies, the student performs language drills orally, turning an otherwise monotonous chore into an entertaining effort to be understood by the machine. Educators are taking notice: a school district in Kyoto will let eighth graders use the DS for English vocabulary drills.

English Training has sold half a million copies in Europe and South Korea in the past year. Flash Focus, a Japanese hit that trains users to follow objects with their eyes, will soon be released in the United States and Europe. Then we’ll see if the craze spreads beyond Japan.