Japanese products often have manufacturing plants in countries other than Japan (such as China and Vietnam). For example, even if "Made in Japan" is mentioned on the listing page, the same product may be divided among factories in Japan, factories in China, and factories in Vietnam. Products listed as "Made in Japan" on the list page are designed by Japanese company, prototyped in a factory in Japan, and checked for performance and quality.
After that, in the mass production stage, it may mean that part or all of the total production volume has been transferred to an overseas factory. Of course, overseas factories are manufactured using the exact same manufacturing process as Japanese factories, and quality control is performed.