Tokyo Game Show 2017, one of the world's top gaming industry events, kicked off Thursday near the capital, with competitive video gaming, or eSports, under the spotlight.

A stage for the "eSports X" event was set up at the four-day video game software and hardware expo at the Makuhari Messe convention center in Chiba, east of Tokyo, introducing a total of eight game titles. It involves professional players of eSports, an abbreviation of "electronic sports," competing for prize money.

The eight titles included GungHo Online Entertainment Inc.'s "Puzzle & Dragons Radar" and Konami Digital Entertainment Co.'s "Winning Eleven" series, both popular in Japan.

Some 600 companies from around the world will showcase roughly 1,000 titles at the annual event expected to draw roughly 250,000 game fans, with some 1,300 booths open for hands-on experiences of new titles and other products, the organizer said.

Tournaments of eSports are held around the world, usually in arenas packed with spectators, with North America and South Korea the largest markets. Arenas are now being built specifically for eSports events, while professional sports clubs and leagues are sponsoring players.

According to estimates by market research company Newzoo, eSports will be a $696 million industry in 2017 and total revenue by 2020 is likely to reach $1.5 billion. The number of eSports fans is expected to grow 50 percent to 286 million in 2020, from 191 million this year.

But Japan, which has produced best-selling game consoles and software, has largely been left out of the boom due to legal hurdles that categorize giving prize money for gaming as a form of gambling.

"At first I did not have a positive image of eSports as it seemed something introversive. But eSports is actually no different from watching real sports games," Takeyoshi Yamada, deputy editor of Nikkei Technology Online, said in a key note speech.

"I hope to turn the Japanese eSports market into one that is big and fun, like overseas," he added.

Hideki Okamura, head of the Computer Entertainment Supplier's Association said the eSports business will not only contribute to enhancing Japan's gaming industry but also global competence. "I also believe that eSports will (step up the presence of) games in Japan," he said.

Another highlight of the annual game show is Capcom Co.'s new title "Monster Hunter: World" that is set to be released in January next year. Visitors will be able to experience the new title at the event.

The show will be open only to the media and gaming industry for the first two days, then to the public on Saturday and Sunday.

Japanese game giant Nintendo Co., which launched its successful Switch game system in several major markets in March, is not participating, having forgone the event since it began in 1996.