What is this red orange insect with black dots found in Japan?
I was able to find it in an insect lexicon. It is all in Japanese, but the description fits the image. The insect is in fact a カミキリ、a ホシべ二カミキリto be exact. And the binomial name is Eupromus ruber

Here is also some more information https://www.insects.jp/kon-kamihosibeni.htm
And a Wiki page in english https://en.m.wikipedia.org/wiki/Eupromus_ruber