When we ask Tanabe, about his next key ingredient, he shrugs and says he's not sure.

CNN: Tokyo restaurant dishes up the dirt

Tanabe tells us the soil is first lab tested, and then heated to extreme temperatures, to kill off any bacteria.

CNN: Tokyo restaurant dishes up the dirt

"I'm confident that some kind of agreement will be worked out in Kyoto, " says Toshiaki Tanabe, Japan's ambassador for global environmental affairs.

CNN: Hot Air In Kyoto

After that process is complete Tanabe will work it into his menu.

CNN: Tokyo restaurant dishes up the dirt