Nintendo shares soared more than 20 percent Monday morning, extending a rally sparked by news that its smartphone game debuted at the top of gaming charts as the game has become an unexpected craze, adding $9 billion in market value for the company.

The video game giant jumped 3,310 to as high as 20,270 yen -- the maximum daily limit -- as Pokemon GO -- which connects a user's real-world location to the game as they try to catch on-screen characters -- launched in the US and Australia and was an immediate hit with fans. Server problems because of overwhelming demand have delayed the international rollout of the game to countries such as the United Kingdom and the Netherlands, Niantic said.

The game allows players search parks, buildings, subway stops and other locations for characters such as Pikachu. The game is an example of "augmented reality," blending a person's view of the real world through the smartphone's camera with digital images of the colorful characters.

The game, a joint project by The Pokémon Company, which is 32%-owned by Nintendo, and Niantic Inc., allows players search parks, buildings, subway stops and other locations for characters such as Pikachu. The game is an example of "augmented reality," blending a person's view of the real world through the smartphone's camera with digital images of the colorful characters.

In March, the Super Mario maker released Miitomo, its first-ever mobile game, as it moved away from a longstanding consoles-only policy.