The closest I know of is ABBYY Screenshot Reader, it has a trial version for a couple of weeks. It's an OCR that can copy the japanese text on the clipboard, but as far as I know it can't auto translate it. If you can code a bit, you can automate the translation e.g. Through Google Translate with a popup after ABBYY does its OCR. Here's a relevant example with AutoHotKey. Source: about 3 years ago

-Pressing Shift+ or Ctrl+ or Alt+ the right click button will re-enable the menu - Using the built in reader view to see if it allows access or try to save the website, or save markdown (joplin or a markdown website saver). - Using browser built in "reader view/mode" to see if it allows access to text or try to save the website, or save markdown (joplin etc). -Screen capture like Screenshotcaptor... Source: about 3 years ago

Tyke (Free) Not a trike but a tyke! (I'm so sorry)... A little bit of scratch paper 📝 that lives on your Mac menu bar. Source: over 1 year ago

I'm moving to Linux/Gnome from macOS. There is a little app for Apple's OS that I use a lot: Tyke. It's utterly simple, basically an icon on menubar that holds a text field where I can't type or paste anything I want in plain text. When I reboot the system, it vanishes. Source: over 2 years ago

I use the free Tyke all the time. Don’t mind at all that it has few features. https://tyke.app/. Source: almost 3 years ago

For a simple(r) no non-sense, free, no markdown just plain text alternative, check out Tyke: https://tyke.app. Source: almost 3 years ago

Tyke is the most dead simple option I've seen. https://tyke.app/. Source: about 3 years ago