There are very few English resources on Saito. The fullest is a recent exhibition book (Saito Kiyoshi: Graphic Awakening) that follows overviews on his life and technique with brief sections on the genres he worked in. It’s hardly comprehensive as it claims but it gives more structure and examples than the other treatments I’ve found. Online there are brief (and mostly overlapping) biographies at two of the better dealer sites (Ronin Gallery and Moonlit Sea, with bibliography on the latter). These also feature works for sale while Ukiyo-e hosts a larger selection aggregated from a number of collections. Past that, Google is your friend since the best compilations are all in hard to find (and expensive when found) Japanese volumes.
But here are some of his cats. There’s a clear progression from the less stylized earlier row (1940s-50s) to the hyper-elongated (sometimes owl-ish) geometrics of the second row (1950s-70s) and later back to something of a blend in the third row (1980s, though the right-hand piece is, as best I can tell, a late revision of an earlier one from the 1960s).
Extracts 