I saw a random picture of a handmade Guu-Watanabe bag back in 2006 and thought it was the most elegant design I had ever seen. (I urge you to spend some time exploring the design options now available on their website).
Shortly after seeing one of these bags, I tracked down the maker, Watanabe Shoichi, in Tokyo and together (with limited common language skills) we designed the bag for my Ebisu, emailing measurements and drawings back and forth until we had the proportions just right. I believe I was his first customer outside of Japan.
I’m still delighted with my purchase. It was — and still is — impossible to get a bag this size. It is much bigger than either the Ostrich bag or the Berthoud and it fits the proportions of my 59cm 650B frame just right, as I think is very clear in this photo.
The only flaw — if you can even call it a flaw — are the straps and metal buckles (a slightly fussy or showy detail that has no place in classic randonneuring designs). I would have preferred simple elastic and hook closures (and I notice that Shoichi now uses this type of closure on his current line), but otherwise it is perfect.