
I really hope the team scanlating this gets around to it but there’s actually a series of extras that sensei posted on her twitter going over both Tetsuki & Chika’s past as well as chika’s relationship with his dad. Turns out chika’s mom left them for some other guy when Chika was still really young, and he has the unfortunate luck of looking almost exactly like her. Chika’s dad’s job was also not exactly easy (or going well at that point I think?) and then he suddenly became a single father. According to the dad’s words, everything went off the rails after Chika was born. Chika being a precocious fighter since elementary school (usually in self defense mind you) didn’t help much, especially with how his dad’s job kept getting more and more demanding and yet having leave to leave work to get your kid from the police station or school for fighting? A lot of stuff built up and it got worse and worse until grandpa stepped up — and then grandpa dies.
Once, when the dad was drunk, he talked about how he didn’t want to be such a parent either but no matter how hard he tries he can’t bring himself to love Chika. This manga always finds a way to make me cry but the pain and rage I felt after that scene watching itty bitty baby probably like seven year old Chika lay a blanket over his shitty father while apologizing for his own birth….

Wow that's... Poor Chika. ╥_╥ Now I don't know if it's better if he was actually just a tsundere. But that's... If he couldn't properly care for the child or even love him, he should have just left Chika to his grandpa much earlier. Maybe at least Chika would experience a much more loving childhood than what he had experienced. ┗( T﹏T )┛

I dont think the dad realised he COULD leave the kid to grandpa. Because, y'see,in most asian cultures, in general, raising kids is considered a woman's job. If it was grandma, instead of a grandpa, the dad would'nt have throught twice to send him away.
But grandpa is a man, plus the dad and him already had a bad relationship because he didn't want to be koto player, so the dad probably felt he couldn't trust the grandpa to singly raise the kid by himself.
If it turned out that the rift between Chika and his father (before the accident with his grandpa happened) started all because he's a tsundere who couldn't express his own feelings, I'll be super mad. Like, at least Satowa's mother became like that because of excessive pressure and expectations (still unreasonable tho imho). ┑( ̄Д  ̄)┍