The Bank of Japan is already powerless to save the yen whether it raises rates or not.

Even if the Bank of Japan raises rates, it can only do a mild hike. If it carries out a violent rate hike, the system will collapse. But a mild rate hike is also not enough to address the issue of the exchange rate weakening.

The Bank of Japan will put on a show of expectations for a violent rate hike, and then at the decision meeting it will present a mild rate hike option.