It will be hard to replace them, and lead to atleast a short to medium term disruption:
- Photoresist
- Tokyo Electron Lithography machines
- Precision bearings, specially ones already designed into chinese products
- MLCC Murata, both low-end and high-end
- Industrial equipment - robotics, robot components, etc.
I am aware that there are Chinese competitors in all fields, but even if their products were equally performing (which they are not in many fields), even then it will take time.
Apart from that Japan is a big customer for Chinese goods, a big market.
Currently none, both need each other. But if China has alternatives for Japanese suppliers, so does Japan have alternatives for Chinese suppliers.
That's literally what I just wrote, will be very selectively applied to MIC only, and hence not in line with what everyone else is saying.