Asian markets were mixed on Tuesday after comments from Japan's finance minister about monetary policy and the government's eagerly anticipated stimulus program added to nervousness about the outcome of the Bank of Japan's Thursday meeting.

Taro Aso told a press conference the government hadn't decided on the size of its stimulus package, with more details expected next week. He also said it was down to the Bank of Japan to decide on monetary policy but he hoped the Bank of Japan would do its best to push inflation up to its 2% target rate, the Financial Times reported.

The yen rose in the wake of Aso's comments.

One dollar recently bought ¥104.4500, down 1.30% and close to a one-and-a-half-week low, while the euro lost 1.14% against the Japanese currency and was recently trading at ¥115.0100.

The yield on the Japanese 10-year bond was down 1 basis point at minus 0.26%. 

"An imminent shift from fiscal tightening to loosening has reduced the pressure on the Bank of Japan to provide more stimulus," said Capital Economics. "However, the sharp appreciation of the exchange rate since the start of the year is threatening to derail the Bank's efforts to lift price pressures, and we expect policymakers to step up the pace of asset purchases and probably also cut the interest rate on excess reserves at the upcoming meeting." 

Also, in Japan, a 26-year-old former employee killed 19 people as they slept at a facility for the disabled, and wounded many others.

The Nikkei 225 fell 1.43% to 16,383.04, while the Topix was down 1.39% at 1,306.94.

Toshiba led the Nikkei 225 lower, falling 9.3%. Other exporters including Toyota Motor (TM - Get Report) fell. That stock was down 2.5%.

SoftBank (SFBTF) recovered from a recent selloff after its agreed $32 billion bid on July 18 for U.K. chip designer ARM Holdings and was the leading riser on the Nikkei 225, gaining 3.4%.

Nintendo (NTDOY)  closed up 1.6% after falling 17.7% on Monday on news that the soar-away success of Pokémon Go wouldn't translate into an increase to the company's full-year profit forecast.

In Hong the Hang Seng was up 1.15% at 22,246.05. On mainland China the CSI 300 rose 0.87% to 3,259.04.

Brent crude was recently up 0.29% at $44.85 a barrel.