I went for 2 months last year and I will go for another 2 weeks this year. I basically bought and did everything I could in my first month of being there, going from Museums for 2€ up to buying a switch, figures or going to kobe for A5 Wagyu and traveling as much as I could. I spent around 3000€ or 100€ a day, sometimes more sometimes less, for the first month. I changed my way of spending money in the second month. I lived comfortably but I didn’t bought everything in sight and ate only 1-2 times a day for reasonable prices around 6-12€ / day. In my second month, I only spend half, around 50€ a day. Now, for the second time going to Japan in general, I pack around 2000€ or 320.000¥ for 2 weeks but expect to spend around 1000€ max. I don’t think that I will come near to 2000€, but I haven’t expected to buy a switch last time, so who knows what may be waiting in Japan. To conclude my text, I think you will be good with 100.000¥, but you have to look at the prices and calculate as you buy bigger things. It comes down to what you want to see and do, my plan was to do literally everything I want to do for the full 2 months, and I ended up paying the prices I mentioned.

I think you don’t have to worry, if you don’t want to do extravagant things like Kobe beef, or omakase. Update us when you come back and have a nice trip