Sponichi is reporting that the Oakland Athletics offered Hisashi Iwakuma a 4-year deal worth US$14M - 16M (about 1.162B - 1.245B yen).
Averaging out the A's offer over 4 years would put Iwakuma's yearly salary between US$3.5-3.75M (or 290M to 311M yen). And for Iwakuma, who made an estimated 300M yen this past season, that apparently isn't enough.
And while Iwakuma's agent Don Nomura isn't letting out too much information at this time because the two sides are still in the middle of negotiations, it appears that they're looking for Daisuke Matsuzaka money: yearly average of about US$8.67M.
On top of all this is also the fact that the exchange rate for converting dollars to yen is absolutely horrific right now. When Matsuzaka signed his contract with Boston, the conversion rate at the time (somewhere around $1 = 118 yen) meant he was pulling in about 1.023B yen a year. That same amount will now get you about 724M yen (somewhere around $1 = 84 yen).
In any case, the A's and Iwakuma have until the end of December 7th to come to an agreement so there's still time. It could come down to the wire, just like the Matsuzaka signing.