Maybe things are different with Japanese immigration authorities, but posting this feels dangerous.
In other countries there's a lot of attention on "fraudulent" visas, and it's often vague what "fraudulent" means. I'd be worried that some of the 'tricks' in here (the admission that the business doesn't really need to be in Japan, the office arrangement, etc.) could make immigration authorities revoke the visa if they feel it was done under false pretences.
While I agree if he were doing anything questionable, IDK, my reading is that he's exporting software development services from Japan and paying taxes in Japan correctly on both business income and personal income incident to doing this.
Yup I agree. Japan sets and enforces the requirements as they see fit. It sounds like they are pretty much happy to let anyone in as long as they’ve got ¥5,000,000 and a plan to start a business in Japan.
They clearly keep you on a short leash with the yearly renewal requirements to ensure you are paying taxes, following laws, and are unlikely to become a burden on society.
They may change the requirements in the future, but in a country facing severe population decline, just paying taxes, supporting the health care and social security systems, and spending money with local businesses may be sufficient to justify handing out the visa.
In other countries there's a lot of attention on "fraudulent" visas, and it's often vague what "fraudulent" means. I'd be worried that some of the 'tricks' in here (the admission that the business doesn't really need to be in Japan, the office arrangement, etc.) could make immigration authorities revoke the visa if they feel it was done under false pretences.