It was a sudden decision by Ludwig and myself Sergey but you'll be happy to know I suffered the entire 3 days like I've never suffered before. The heat at times was unbearable and I never found my legs for even 1 minute. I don't think I've ridden slower I'm in the process of blogging it with photo's and maps so stay tuned!
If you really must do Otoge then one option could be to reverse the loop, attacking Sasago first, Yanagisawa etc, then after Matsuhime turning right onto the abandoned north side of Otoge (I heard that descending the north side is pretty perilous - hence the switch of directions). This would save you having to go all the way back to Otsuki.
I did it on my own once, but it's a bit lonely out there; climbing Yanagisawa from that direction would also be pretty exposed as well).Wow, thinking about it, it's just a really hard looking route. good luck.
Did it! Best ride I have done - by a wide margin. Great to step out the car among the big mountains. Enjoy Matsuhime in the morning sunshine and Otoge in the late afternoon - even the monkeys were surprised to see a cyclist at 17:00. No riding out and back to Tokyo on congested river paths or roads. Just one superb climb after another and each comes with a glorious descent.