The first Japanese drama I watched was Oshin. Also I have watched the story of Ohara Ithoko. I haven't watched a Japanese drama in years. @Elina xi , do you have any recommendations for me? I know that you're an expert of Asian dramas.
A really underrated one that I love is called "ashita mama ga inai", which translates to "tomorrow, mom won't be here" and is about the life of orphans. The drama was unfortunately cut short due to government and orphanage disapproval by most of the country, so funding for the show was ultimately cut. It's only 10 episodes long, but the kids did such an amazing job for such a dark show.