Honestly, skip that SmallRig grip. It basically ruins the stealth of the RX100 series. Unfortunately, I had issues with third-party grips peeling off after just a few weeks of use. For Japan, you really want to keep things compact and reliable. Here is what I consider essential for a safe trip:

• Sony NP-BX1 Rechargeable Battery Pack - dont rely on power banks because charging in-camera is slow and can strain the port over time.
• Sony PCK-LG1 Screen Protector for RX100
• I unfortunately scratched my first unit because the screen glass isnt as tough as expected.
• Peak Design Cuff Camera Wrist Strap - provides way better security than the flimsy string in the box. Its really not as good as people say to just use a power bank while walking around. It gets hot and is honestly just a disaster waiting to happen if the cord snags.

Been thinking about your Japan trip since I did Tokyo last year with the same camera. I tried the whole power bank thing but having a cable dangling in my pocket while walking through crowded stations was kinda annoying. Regarding the grip issue, I've compared a few setups. The Sony LCJ-RXK Jacket Case is a decent option if you want protection, but it’s a hassle to remove for every SD card swap. I much prefer the Sony AG-R2 Attachment Grip instead. It is just a small rubber piece that sticks to the front. It adds basically zero bulk but makes the camera feel way more secure. For those night shots in Shinjuku, I'd grab a Manfrotto PIXI Mini Tripod. It is small enough to fit in a coat pocket and way more reliable than balancing your camera on a vending machine or railing.

Re: "Been thinking about your Japan trip..."

• Agree on the cable mess. In my experience, safety is key:
• SanDisk Extreme PRO 64GB SDXC UHS-I
• LensPen NLP-1 Dont risk losing those memories!