A new visual search tool called Hitotsunagi (Connecting People), developed by NTT Resonant, allows users to explore the relationships between Japanese celebrities and historical figures. Launched this week on Goo Labo (Goo Labs), an offshoot of portal site Goo, the tool makes use of a rich indexing technique developed by NTT Cyberspace Laboratory that extracts contextual relationships based on online data found in the news and blog entries.

A search on a famous name produces a bubble at the center of the screen around which a number of smaller bubbles pop up, linked to the central bubble; tags displays the nature of the surrounding connections. Clicking on one of the related people moves them into the focus of a new search.

The tool, which resembles Google's Wonderwheel,  is impressively smooth and swift, though the results of our searches were a bit hit and miss. While historical figures like Ieyasu Tokugawa brought up images of paintings, searches for well-known, contemporary names such as Ryuichi Sakamoto came up blank. And according to Hitotsunagi, actor Shun Shioya, born in 1982, is the "father" of actress Misako Renbutsu, born in 1991. Oops.

Glitches aside, Hitotsunagi should be rather educational for Japanophiles wanting to put things quickly into perspective. NTT Resonant is keen on pushing the interface envelope, and it is indeed a fun tool to play with, but the devil in me would love to see relationship categories beyond family members and friends, such as rivals and ex-lovers, just to spice things up a bit.

The service will be available until Dec. 31, 2010, and currently only searches Japanese text. One wonders if the tool could be extended to the rest of the word. It would be an excellent global manifestation of Stanley Milgram’s Small World Experiment.