This is a gem
The fact that the age gap between grandpa and student is immensely huge (around 40 years!!!) is incredible. Not bcs of the age gap but the fact that the author were able to pull off a great chemistry between these people from 2 different generation.
Just hoping that we get a sequel. I mean, we left sensei divorced, alone, and sad. He deserves a new story, maybe a new boyfriend to make him happy *wink*
Gray to Blue no Ai Made