According to reuters the shares of Japan's Nintendo Co Ltd soared again on Monday, bringing market-value gains to $7.5 billion in just two days as investors cheered the runaway success of Pokemon GO - its first long-awaited venture in mobile gaming.

The game, which marries a classic 20-year old franchise with augmented reality, allows players to walk around real-life neighborhoods while seeking virtual Pokemon game characters on their smartphone screens - a scavenger hunt that has earned enthusiastic early reviews.

In the United States, by July 8 - two days after its release - it was installed on more than 5 percent of Android devices in the country, according to web analytics firm SimilarWeb.

It is now on more Android phones than dating app Tinder and its rate of daily active users was neck and neck with social network Twitter, the analytics firm said. The game is also being played an average of 43 minutes a day, more time spent than on WhatsApp or Instagram, it added.