From a UFC press release:
Ishii, who won the gold medal in the men's over 100-kilogram event at the Beijing Olympics, arrived in Las Vegas on Christmas day to experience UFC 92. Over the next two days, Mr. Ishii toured Las Vegas and visited various MMA gyms, including the UFC Training Center and Xtreme Couture, where he trained and sparred with Randy “The Natural” Couture.
Earlier this month, Mr. Ishii decided that he wished to start his MMA career in the United States, and that his dream was to fight in the UFC. He made his choice to negotiate with UFC last night after watching UFC 92.
“I was impressed with the training programs here in Las Vegas and the UFC event,” said Mr. Ishii. “I am looking forward to working with the UFC and to developing my mixed martial arts skills.”
“Satoshi Ishii has the potential to be very successful in mixed martial arts,” said Dana White, UFC President. “We can't wait to start working with Mr. Ishii, we look forward to helping him with his training, his career, and his eventual debut in a professional fight.”