This information has been out there long enough for me to link to an English source.
Hitoki Iwase, who earlier in the offseason declined to file for free agency, signed a four-year deal to remain with Chunichi. His salary in the first season of his contract will pay him 430m yen ($4.73m at today's exchange rate), with salaries to be renegotiated yearly afterward. But according to Iwase, money wasn't the driving issue:
"I realized that I am not cut out to pitch overseas," said Iwase. "I originally joined this club because I liked it and the environment suits me. I'm determined not to let the team down and to make sure that I fulfill my role in games we can win next year."
Given the weak market for MLB relievers this season, Iwase did well financially, at least for the first year of his contract. We'll see how the deal looks in a few years. Iwase will be in his late 30's by the time the deal ends, making him likely to be a lifelong Dragon.