Average Co-Inventor Count = 2.67
ph-index = 2
The patent ph-index is calculated by counting the number of publications for which an author has been cited by other authors at least that same number of times.
Company Filing History:
1. Nippon Gakki Seizo Kabushiki Kaisha (2 from 841 patents)
2 patents:
1. 4567804 - Automatic playing musical instrument
2. 4469000 - Solenoid driving apparatus for actuating key of player piano