Izumi Sato has added another great video of Yuza Sashiko to youtube - click here to watch (soundtrack in Japanese but with some English info in the video info box).
Yoshimi ARIMOTO told us about Yuza sashiko ca.20 years ago. NHK TV interview.Chie Ikeda has learned the basic Yuza sashiko patterns from Yoshimi Arimoto. Mrs. Arimoto says that Yuza sashiko is to stitch without line. The basic Shonai sashiko patterns was arranged by Tojiyo Takahashi & Chieko Hori including Kogin patterns, Nagai sashiko patterns, Yuza sashiko patterns.
The video streaming isn't very good on my internet connection - let me know if it runs smoothly for you.
EDIT - Izumi has added some more information about the sashiko patterns to the YouTube description and comments section. The 'Nagai' patterns are from Nagai District, Yamagata Prefecture ('nagai' is a word for 'long' in Japanese, so I thought she was writing about long patterns!) Hanabishizashi (flower diamond stitch) is one of them. She sent a photo of Chie Ikeda's sashiko waistcoat (modern style) from 'The Ultimate Sashiko Sourcebook' to illustrate this - the flower shaped pattern is hanabishizashi (shown by the paper arrow, centre page) and the other labelled one is also from Nagai.
Izumi is the historian of Yuza and Shonai sashiko patterns and wrote the history sections in the sashiko books published by Yuza Sashiko Group.
6 hours ago