A youth named Kiriama Rei, who lost his family as a child, endures loneliness to become a professional shogi player. Then, through a chance meeting, he develops a relationship with the three Kawamoto sisters, who hail from a working-class district of the city, and little by little his frozen heart begins to thaw.

You might know Umino Chika from Honey and Clover (or you might not). Her art is very cutesy but the content is much more than you'd expect at first sight.

3-gatsu no Lion is a wonderful drama/slice of life that can be both heartwarming and heartbreaking. It has a cast of diverse characters that increases as the people in the main character's at first isolated life increase. The relationship dynamics are interesting and the slow character development very well done.

And a note that needs to be made for a story with this kind of subject matter: yes you can read it without knowing/caring about shogi (though you might learn a couple of things about it along the way).

Please read obscure manga about shogi boy and friends.