How was he able to fish for money when he came initially on a visitor visa?

"Once the motivated young man turned 21, he had saved enough money for a round-trip ticket to Dallas, Texas. And more importantly, he felt he had the skill to fish against the best fishermen in the United States at the 1991 BASS Invitational on Sam Rayburn Reservior.

Tak lands in the USA

With an international driver's license and $2,000 in his pocket, Omori rented a car after landing at DFW airport and drove to Rayburn. "It was really confusing, because the steering wheel was on the wrong side of the car and everyone was driving on a different side of the road. It took some getting used to," Tak remembers. Luckily, he had time to practice."

https://www.bassmaster.com/hiros-journey

That would be illegal per his visa, assuming he came here on Tourist/Business Visitor Visa......

You are pretty hung up on this. Its a moot point. You don't know what kind of VISA he came here under and it was 25 years ago. I'm willing to bet he had his ducks in a row.

I drew Tak on Ross Barnett in the early 90's. He spoke no English and of course I spoke no Japanese. I was sitting on my jacket with my truck keys and his truck keys in the pocket. Tak was not a good boat driver. He hit a wave at the wrong angle and so hard that it bounced both him and I all over the bottom of the boat. When we recovered I noticed that the jacket was now at the bottom of the lake. I don't know what he was saying but it sounded like some kind of cursing and I was sure he wasn't understanding my strongly worded emotions either. We had to call a locksmith out. He was living in a van. In the end we were both laughing, or I think that was what we were doing. Yes I know the keys should have been in the glove box, but they weren't and that's probably what he was yelling about. LOL