Ms. Watanabe underwent 420 hours of training and lectures on teaching Japanese before going on to become a full-time lecturer at a Japanese language school in Bangkok. After returning to Japan, she served as a sales associate at Recruit Holdings while also volunteering on weekends to provide Japanese lessons for foreigners in Japan.

In 2000, she and her fellow volunteers founded a school to offer part-time lessons to foreign residents. Founded on the principle that "having fun while studying accelerates the learning process," they focus on original content to ensure fun and effective lessons. To date, the school has provided Japanese lessons to over 3,000 students with flexible, reasonable, and conversation-focused instruction.

In 2009, she and her staff co-authored the textbook Nihongo Fun and Easy for beginning learners of Japanese.