Ikawa was severely injured, but survived; Nakanishi, who sustained a spinal injury, did not.
The National Police Agency told the Japan Times that the tragedy is the first fatal accident involving the augmented reality game that they are aware of, though there have reportedly been nearly 80 accidents in Japan involving cars or bicycles since the introduction of the app, Channel NewsAsia reports.
Pokemon Go, a game that became a global sensation immediately following its launch in July, has already been blamed for a wave of crimes, traffic violations and complaints in cities across the globe.
The game has recently added a feature that alerts you when you are moving too fast and appear to be in a vehicle, and prompts you to confirm that you are a passenger before you can continue.
Earlier this month, Iran became the first country to ban Pokemon Go over security concerns and the Israel Defence Force has also banned soldiers from playing the game while on duty.