Took the Tamron 28-75mm f/2.8 Di III VXD G2 to Kyoto, loved it! Much sharper than the Sigma 28-70mm f/2.8 DG DN Contemporary, though Sigmas way lighter. Tamron is just amazing!

I've been shooting with Sony for years and honestly, the search for a single lens usually ends in some kind of compromise, but usually a good one. When I went to Hokkaido a couple years back, I brought a bag full of heavy glass and ended up leaving most of it in the hotel room anyway. I realized that for Japan, you really want range because one second you're shooting a tight street in Shinjuku and the next you're looking at a temple from across a pond. If you want to save money, definitely check out the buy/sell forums on Fred Miranda or just browse the older threads on the DPReview forums. It helped me stop overspending on gear I didnt really need. For your 900 budget, these are my picks:

• Tamron 28-200mm f/2.8-5.6 Di III RXD - its light, fits your budget brand new, and starting at f2.8 is huge for night shots in Osaka.
• Sony FE 24-105mm f/4 G OSS - hunt for this used. Its got that constant f4 and the build quality is top notch. Ive been incredibly satisfied with the Tamron tho... it just works well without making my neck hurt after a long day. Dont get too caught up in the 35mm vs zoom debate yet, for a first trip, flexibility is your best friend. Plus you'll have plenty of cash left over for some serious ramen.

Im literally struggling with this exact same choice right now for my own travel setup. Its tough balancing constant aperture vs focal range specs. These are the ones I've been comparing for my trip:

• Sony FE 24-105mm f/4 G OSS for the corner sharpness and OSS.
• Tamron 28-200mm f/2.8-5.6 Di III RXD for that insane versatility. Searching for a single lens is basically a nightmare tbh.