Japan is on holiday today, but that is irrelevant to yen buyers.

USD/JPY to its lowest in 12 months, without fresh news nor data to drive it (none is needed, as I've been saying for a while now):

usdyen lowest in a year 16 September 2024 2

The USD is lower pretty much across the board also. Even AUD, which had been troubled by the poor data from China over the weekend, is gaining against the big dollar.