Do I spy a fellow T-Square fan? You have any other recommendations? I've found a few related bands in the Casiopea/T-Square family but I have a feeling there's a whole iceberg left to delve into if I can find it.
Other than the artists I mentioned, I also enjoy Masayoshi Takanaka, Kazumi Watanabe, Horii Katsumi Project, Dimension, Trix, Prism, and Fragile. Which reminds me that Fragile's drummer, Kozo Suganuma, also died relatively young a couple years back, at 62.