Did you listen to the 2010 recording from Akira Ifukube Works for Piano, Volume 2? That recording required two pianists on the second piano. What I watched yesterday was a live performance of the piece performed by Reiko Yamada on the first piano and Patrick Godon on the second. The 2010 recording was also performed by the duo with Brett Rowe being the other pianist on the second piano.
I’m not too sure, but two of the hands definitely belonged to Reiko Yamaha 🙂