By far, the biggest crowd pleaser at last week’s TechCrunch50 was a demo by the Japanese startup Tonchidot for a mobile social tagging product it is developing called Sekai Camera. The Japanese CEO Takahito Iguchi overcame a very noticeable language barrier and deflected serious questions from the judges through sheer will of character. He had the audience roaring in laughter and rooting for him, as he answered lengthy questions about how his service would actually work with brief responses such as “Imagination!” and “We have a patent.” When judge Rafe Needleman suggested that Google would buy Tonchidot, he objected: “Never!”

The original video portion of the demo has been watched more than 108,000 times on YouTube. But I’ve embedded the entire demo above, including the follow-up Q&A. The entire video is 17 minutes long and takes about a minute to get started, but it is captures how Iguchi had the audience, and even the skeptical judges, eating out of his hand, despite a limited grasp of English. The Q&A starts about 8 minutes in. Iguchi was particularly adept at exasperating judge Tim O’Reilly. There is also a shorter edited video on YouTube of the judges’ Q&A with subtitles (embedded below). Anyone doing a demo can learn from this: keep your answers short, don’t drown in details, explain how you will change the world.

The demo starts with a video showing how Sekai Camera uses the iPhone’s camera viewfinder to overlay tags and information from a database onto objects in the real world. (I am not sure the iPhone SDK allows developers to access the camera in that way, but never mind). Pan the camera around, and different tags will pop up for stores, products, even voice or text notes left by your friends. “Look up, don’t look down,” Iguchi kept telling the audience. Sekai Camera includes an “Air Filter” that lets you see just the tags you are interested in. It is designed to be an interface between the real world and the Web.

We allowed a canned video demo instead of a live demo in this one instance because it was really the only way to show the full capabilities of the product (during rehearsals TC50 organizer Jason Calacanis did see a functioning prototype actually working on an iPhone). The judges, though, wanted to know who will be doing all of the tagging, and whether this thing really works. To which Iguchi answered, “Join us.”

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