18 years old, can I buy cigarettes to take back when I travel to Japan?

When you meet that kind of rigid clerk, you will be asked to show your ID. The average shop assistant looks at your face and clothes. If you look sixteen or seventeen, the clerk will ask you to show it. It doesn't have to be like this. If you are over 20 or look older, I can buy it for you. If one store asks you to show your passport, retreat to another.