Here is a fast way to copy Japanese words of RTKXI and then translate them :
1. Take a screenshot (Alt + Print screen) from the game :
2. Paste it into the Paint and omit the other parts :
3. Go to the Google Drive and upload the picture :
4. Right click on the uploaded file and then select Open with > Google Docs :
5. Now it is possible to copy the Japanese words :
6. Use Google Translate :