Advice for window insulation please!

It’s getting reeeaall cold in Hokkaido now :,) I’d really appreciate any tips on shoji window (and and door) insulation!! I’m getting tape tomorrow but I’m wondering if there’s anything that’s a positive work or improvement to really keep the heat in and cold outside.
I’m getting insulation tape and bubble wrap tomorrow.

Is there anything I’m missing or a product you might strongly recommend? DCM is the closest home goods store me so I’ll be checking what they have there!

by crihmson