It all started in early 2021 when Philip Chuah, a watch enthusiast in Singapore, asked some local artisans about the cost of a custom alligator strap for his Omega Speedmaster Racing model.

They said 400 Singapore dollars ($290). “I was only earning about 1,000 a month, so that’s almost half my pay on just a watch strap,” he said. “And I thought, ‘I’ll just make it myself.’ And somehow it got to the point where it is today.”

Now Mr. Chuah operates Atelier Kai (Kai is part of his Chinese name). He primarily makes leather watch straps, as well as some wallets, a crossbody clutch bag and a few small leather-goods items. And while he would like to expand his line, he said, “right now I don’t really have the time to experiment with other items, with the straps orders that I have.”

This year Robin Wong, a watch collector in Singapore who posts as @watchthebin on Instagram, has purchased five straps from Mr. Chuah. “His straps are special because he has a vast range of colors and leather to choose from,” Mr. Wong wrote in an email. “I especially like his bold colors on his exotic leather, many of which are uncommon.”

Before he started the business, Mr. Chuah, now 28, had no experience with leather work. “In Singapore’s education system, you don’t actually have that many opportunities to express yourself creatively and work with your hands,” he said. “Sometimes it feels quite surreal that I’m able to make straps like this.”

Mr. Chuah earned a law degree from the University of Leeds in England and, after returning to Singapore, was studying for the bar exam in 2021. A lot of the city was still working from home in the pandemic when he began trying to make straps, “so it allowed me to explore this passion on the side,” he said.

And although he was called to the bar last year, he decided not to work as a lawyer, at least not now. “I was not feeling the burning passion to become a lawyer,” he said.

He learned his strap-making skills by watching YouTube videos, deciding that he didn’t want to pay the 200 dollars that an eight-hour training course would cost.

However, he noted ruefully, he has bought every tool used by every person in all the videos: “Right now, I’m probably using maybe 10 percent of all the tools that I’ve ever bought. And if I add up the cost of all the tools that I bought, it’s way more than $200.”

Still, he has no regrets and sees the benefits of being self-taught. “Every time I failed, I’d ask myself, ‘How can I improve?’” he said. “Not going for that course forced me to constantly want to improve, constantly want to learn how to make it better.”

He gave some legal colleagues the first few straps that he produced, then started selling them on the Singaporean online marketplace Carousell and set up an Instagram account, which attracted watch collectors, both local and international. “It’s a very small circle, and word spreads fast within niche groups like this,” he said.

Mr. Chuah initially worked from home — like many younger people in Singapore, he still lives with his parents — but on Sept. 1 he began renting a studio in the Paya Lebar area of eastern Singapore. When his customers are local, “I’ll usually invite them over to my studio to have a look at the leathers first,” he said, “because colors will never accurately translate over phone screens versus in real life.” It takes him five to six hours to make a strap, start to finish.

He buys leathers directly from a tannery in Singapore or from a supplier. “Something that sets me apart from others is my experimentation with materials,” he said. “Usual crafters use basic alligator and calf, but I love trying out different materials such as beaver tail, special effect lizards, stingray, sharkskin and tilapia fish.

“I’ve never seen someone use this before for straps,” he said, referring to the tilapia as he displayed a black band with iridescent turquoise accents.

A project he especially enjoyed working on was a custom wraparound case in python for a MB&F HM10 Bulldog. “I used a traditional wet molding technique, meaning you wet the leather and wrap it around the object and clamp it shut and you leave it to dry,” he said. “And when the leather dries, it dries in that shape.” It took him about two weeks to complete the piece.

Mr. Chuah’s straps range from 150 dollars for calfskin to 280 dollars for alligator that is an unusual color or has been specially treated at the tannery. His website warns buyers that the current lead time on orders is 12 weeks.

“I just cover my costs and I’m more than happy with that,” he said. “Many of my clients are not hard-core watch collectors, they are just everyday people who have just one or two nice watches and just want to spice up their watch.”

For now, Atelier Kai is a one-person operation. “I do all the messaging, all the all the in-person appointments. I do all the crafting, social media, posting, preparing items for shipping,” he said. “But I do want to hire and scale in the future eventually because if a business isn’t growing, then it’s just going to stagnate, right?”

He said his parents had been very supportive. “I’d say pretty rare for Asian parents because they want their kids to have a stable income,” he said. “My dad used to refer to my leather crafting as a hobby, but lately he refers to it as work.”