Yes, foreigners can definitely watch sumo matches in Japan. Sumo tournaments, known as basho, are held throughout the year, and anyone can attend as a spectator. The atmosphere inside the sumo arena is electric, filled with excitement and anticipation. If attending a sumo match is not possible, I suggest visiting a sumo stable to witness the morning practice session of the wrestlers. It's important to note that you will need a tour guide to accompany you, as they must make a reservation in advance. It's worth mentioning that not all sumo stables permit visitors, and you cannot enter the stables without prior notice or permission.