The Japanese seem to be crazy in love with massage chairs. Maybe the stresses of everyday Japanese life encourage people there to put a massage chair in their home, but for whatever reason they're popular enough to have a whole section dedicated to them in many department stores.
Why they haven't caught on stateside: For US people the thought of having a chair grip you tightly enough to give you a massage is more than a little unsettling. It seems to be the idea of a "robot" that uses direct physical power over an human being that scares them off a little.
5. Elongated phones
Why they haven't caught on stateside: Style, mainly. But also the overall US trend for technical gadgets "the smaller the better".
4. Blu-Ray recorders
Witness this machine, a Panasonic Blu-ray recorder that can hold up to two terabytes on its internal hard disk, ready to burn that video onto a Blu-ray disc anytime. That's pretty impressive technology, letting users save entire seasons of TV shows before archiving them to disc.
Why they haven't caught on stateside: Americans use video technology differently. Setting up a machine to record TV shows to discs — or tapes, for that matter — is beyond many people. The U.S. rejected DVD recorders because we use DVD machines as players only, with the DVR essentially taking over all video-recording duties. By the time Blu-ray came, virtually no one was recording to disc anymore outside of the PC. Different to the US, the people in the UK already welcomed Panasonics Blu-ray recorder warmly.
Why they haven't caught on stateside: Showers in Japan are used before you get in the bath, and in public baths you're supposed to wash only from the neck down. In the U.S. public baths aren't mainstream, and sit-down showers have pretty much been relegated to bathrooms of the elderly and disabled.
2. Really small netbooks
Why they haven't caught on stateside: Unclear, maybe it's just that with a desktop pc or big notebook at home and a cellphone at hand the US people don't really need this in-between version. Or maybe it just takes another few month until those netbooks make their US breakthrough.
1. Bidet Toilets
No list of curiously popular technologies in Japan would be complete without mentioning bidet toilets. As any visitor will tell you, going number two is a whole experience in Japan, from the first moment your behind touches the heated seat to the built-in stereos to the automatic flush.
Why they haven't caught on stateside: Beyond the sheer impractibility of connecting power cables to every toilet in America, here it's more accepted to catch up on some reading while sitting on the throne. That's entertainment enough for US people. (DVice)