This is a really beautiful little beetle with metallic red/green wing cases (elytra). The species occurs throughout Japan and is also found in Siberia. Apparently it’s a pest of grapes, so it appears on the “regulated” lists in the USA and New Zealand (and other places too I expect). I saw this specimen and immediately crouched down to get a photo, but I moved too quickly and it dropped from the leaf. I thought I’d lost it and was feeling disappointed when it reappeared. But it kept falling from leaves when I was trying to get close enough for a decent shot – very frustrating!
Acrothinium gaschkevitschii (akaganesaruhamushi)