Reading drama "35th Year Love Letter"

65-year-old Nishihata Tamotsu was born during wartime and did not receive a proper education, meaning he cannot read or write, and his beloved wife Kyoko is always by his side.
Born into a poor family and barely able to attend school, Tamotsu grew up to have a difficult time living.
He eventually has a fateful encounter with Kyoko and marries her, but he is so reluctant to let go of his happiness that he is unable to tell her that he cannot read or write.
Six months later, the truth finally comes out and Tamotsu prepares to break up, but Kyoko takes his hand and tells him, "From today, I'm your hand."
Wanting to write a letter of thanks to Kyoko, who has always been by his side and supported him, Tamotsu begins attending night school after he retires.