"juh-POOR-ee" was the pronunciation for this planet's name from the script pronunciation guide. 
According to the Star Trek: Star Charts (pp. 61, 62), the Japori system was located in the Beta Quadrant. This system, also known as Beta Caeli, was a single star system. System primary was a Class F star with a magnitude of +5, which was the same brightness as Sol. In the mid-22nd century, this system was located in non-aligned space. In 2273, V'ger traveled near or through this system on its course towards Earth. In the late 24th century, this system was located in or near Federation space.