This story was produced by our colleagues at the BBC.

If you visit one of the two dozen Pokémon centers around the world, you’ll find toys, stationery, cards — you name it. Since Pocket Monsters was released 29 years ago, their popularity hasn’t died down, and what looks like a simple card game can be sold for hundreds of thousands of dollars.

Even if you’re not into gaming, you’ll have heard of Pokémon. The franchise was a huge success when it launched on Nintendo’s Game Boy nearly 30 years ago and continues to grow. While the Pokémon Company doesn’t release earnings, it’s estimated to have sold $150 billion worth of products.

So what’s the secret to their success? I put that question to the president of the Pokémon Company, Tsunekazu Ishihara.

“I believe the original game was groundbreaking, because they allowed users to exchange Pokémon that you catch with your friends and other players,” he said. “So it wasn’t an introverted activity, but it became a tool to actively communicate with others.”

“The number of Pokémon — which started 151 — has increased to more than 1,000 today, and their fans also grew and now span across several generations.”

What about counterfeits and patent infringement? The company recently sued the maker of the hit survival adventure game Palworld. So what is it doing about those fake Pokémon?

“We’ve been fighting fakes since the beginning,” Ishihara said. “The more popular Pokémon became, the worse the problem. It affects our creativity, and our customers get disappointed when they receive products that aren’t authentic.”

And that’s not their only challenge. Pokémon cards are sold for a price tag of six or even seven figures, Influencer Logan Paul currently holds the Guinness World Records for the most expensive Pokémon trading card, which he bought for more than $5 million.

“If the cards are rare or seen as vintage, their value goes up,” Ishihara said. But, he added “to us, the true value of Pokémon is to play, have fun and communicate with friends.”

Along with Hello Kitty and Super Mario, Pokémon is one of Japan’s three big soft power, and the Pokémon Company is the only one that remains private despite its huge revenue. But the company’s president said that’s not the biggest difference.

“Hello Kitty is one of the characters for Sanrio, and Super Mario is one of the characters for Nintendo — but Pokémon is the only thing we do at the Pokémon Company.”