Nintendo surprised fans on Tuesday by announcing a new chapter in its 40-year-old "Zelda" saga, one of the Japanese video game giant's biggest cash-cows.

During an event broadcast on the web, the firm said "The Legend of Zelda Echoes of Wisdom" would be scheduled for release on the Switch console on September 26.

Eiji Aonuma, producer of the Zelda series, said on the webcast that fans would be able to play as Princess Zelda herself rather than the elf-like warrior Link -- a first for an official entry into the game's cannon.

"This time around Link has vanished and it's up to Princess Zelda to step into the protagonist's role," Aonuma said in comments dubbed into English on the webcast.

Each new chapter of Zelda is eagerly awaited by fans -- the franchise has racked up well over 140 million sales since it began in 1986.

Last year's edition, "Tears of the Kingdom", sold 10 million copies in just three days, Nintendo said at the time. 

The firm showed on its webcast some gameplay from the new title, revealing cartoon-style graphics similar to its 2019 title "Link's Awakening" rather than the sleek realism of last year's entry.

The saga is credited with helping to forge "open world" games where the player is free to roam in virtual landscapes -- an idea later taken up by games from "Grand Theft Auto" to "Skyrim".