I came across this manga by accident and I can't remember what it was called.
The main character is a teenage girl, who lost her memories from when she was young. I'm not sure but I think her last name was Mochizuki, though it might have been one of her friends who had that name.
- I think she has a male friend who carries a sword with him.
- She makes friends with a blonde girl in her class who kisses her in class, apparently thinking that it might bring back some of the black haired girl's memories.
- The blonde girl has a twin brother who also kissed the black haired girl for the same reason, hoping that she will regain some of her memories.
I know it's not very detailed but anything you can think of that matches this description would be helpful.