Request for assistance to obtain a copy of the 1906 Tsutsumi Masao and Higashi Katsukuma book

I've recently been asked to assist in investigating the Tsutsumi Hozan ryu (THR) lineage with respect to establishing Jan de Jong (JDJ) as part of that lineage in teaching THR jujutsu.

As part of that investigation, it has been suggested that Jiu-Jitsu die große Kunst der Selbstverteidigung und vollendeten Körperausbildung, Tsutsumi Masao and Higashi Katsukuma, Berlin, 1906 contains text that says: 'The performance of the students is divided into seven levels, which are reflected in the different colours of their belts.' The colours were in order from beginners to advanced kyu grades: red, yellow, white, green, orange, purple, black and white.

That coloured belt kyu grading system reflects JDJ's original grading system when he began teaching in Perth, Western Australia.

This is an important issue as the conceived wisdom is that the coloured belt kyu grading system (in judo) did not originate until the 1930s, albeit in the UK and or France.

Was there an earlier version of the kyu grades coloured belt system, and even the kyu grades themselves, than is currently considered to be the commonly conceived wisdom? If so, this would be a genuine contribution to the general body of knowledge concerning the judo grading system that went on to become adopted in various forms by many/most martial arts in the world.

With respect to the lesser issue, did JDJ participate in that kyu grading system and therefore used it when commencing teaching in Perth? Are the kyu grades from yellow through to black and white the original THR teachings that JDJ was taught, in the way he was taught (shinken shobu no kata)? Or, given that JDJ had a copy of this book, did he appropriate the grading system (not the content) in that book as his own in order to sure-up the credentials of his teachings? That was, and is not, an uncommon thing to do as is seen in the many schools that attach themselves to JDJ's teachings to sure-up their credentials of their teachings.

When googling Jiu-Jitsu die große Kunst der Selbstverteidigung und vollendeten Körperausbildung, there were no hits directly for that book, however, when googling the authors, there was a hit for Die Selbstverteidigung (Jiu-Jitsu) nebst einem Anhange über Kuatsu (Wissenschaft der Wiederbelebung Verunglückter).

If anyone has a copy of either book or know the locale of a copy of either book, I'd appreciate a heads up.

Thank you,