NJS is Nihon Jitensha Sinkokai or the Japan Bicycle Association. NJS exists to promote the bicycling industry in Japan. NJS is also tasked with regulating Japanese track bike racing, or Keirin. For those who believe the UCI's bicycle design requirements are backwards, Japanese Keirin rules -- established in 1957 -- are downright draconian. NJS specifies weight, frame geometry and material, the number of spokes on your wheels, and every component must have the NJS stamp of approval.
Because the NJS promotes the Japanese bicycle industry, non-Japanese manufacturers have found participation in the lucrative Keirin market very difficult. The list of approved component and frame suppliers consists almost exclusively of Japanese companies.
While the NJS cachet is not necessararily a mark of quality, there's a certain distinction to owning this equipment because the NJS mark is so exclusive. It's a bit like owning a numbered limited production run of a piece of art.
IMPORTANT: Please post comments for this article at the new CYCLELICIOUS 2.0 version of this page.
The NJS MKS Custom Nuevo pedals I have come highly recommended. Though I wish they had a seal on the end that wasn't plastic, the two super-smooth sealed cartridge bearings held together by a single allen bolt are really really nice. The NJS Nitto B125AA alloy track handlebars I occassionally run are light and stiff as hell. I'm going to keep collecting NJS stuff until someday I can afford a Makino to hang them on.
Timely post, as we've had some recent discussions on Flickr with respect to NJS.
Of course, one of the NJS' primary missions is to promote the Japanese cycling industry, so the dearth of eye-tie parts is understandable.
I sure don't understand the fetish, and I can't imagine why someone would want to run a super-narrow NJS APPROVED! saddle on a road-going fixed gear bike, but hey, have fun.
I love when people do Ebay auctions that feature NJS! when there no NJS approved parts included. "My cheap crap hubs would be NJS approved if they had 36 holes and were made by an approved manufacturer." Heh.