My grandmother, Sasaki Atsuko, was one of the most important people in my life. She walked me to the library and played computer games with me. She took me on nature walks and taught me how to bed vegetables in her garden. All my grandmother's grandchildren were special to her, but I like to think that I had a particularly special relationship, because I luckily lived nearby and I spent a lot of time with her.

My grandmother was married to my grandfather for fifty-six years. When they went out once a week for a special romantic date night, their faces still glowed when they looked at one another even though they were in their eighties. After my grandfather died, my grandmother still lived at home and I visited her a lot.

All around the house, there were photographs on every shelf and stuffed in every cranny. My grandmother had five children, nineteen grandchildren, six great-grandchildren, and she also had many friends. All her neighbours would come in to call on her and she would go visit them in return, often bringing me with her. She received packages in the mail from all around the world, since she had friends and relations spread far and wide. She switched between being the President and the Secretary of her flower arranging club and her drumming club, even in retirement. I loved to hear the sound of her drum when she practiced and bring out trays of sweets and tea to her club members.

Sometimes, I would bring photographs to my grandmother and ask her what they meant, what she was doing at the time. She had a beautiful picture when she graduated from university, the top student in her whole year. She had newspaper printouts where she won awards for her work as a software engineer. As well as her day to day work, she was also part of a group for helping women in software engineering, and reading articles about her achievements made me feel inspired to follow my own dreams. I talked to my grandmother about new photographs of my cousins in Switzerland and their adorable baby, about photographs of me toddling around my grandmother's house, about old photographs of my mother when she was a baby in that same house.

When my grandmother became very old, she spent most of her days sitting in her rocking chair in the sun, but she would still always talk to me while I tidied up around the house and helped her daily assistant make her meals. One day, she sat there with her cat in her lap, stroking its fur in the sunlight, and I brought her a very old photo that I had somehow noticed for the first time. I knew that picture had always been there, in a good place on my grandmother's mantelpiece, but I realised that I knew nothing about the story behind it.

That photograph must have been taken a long time ago, showing a young girl about my age with unruly dark hair that stuck up in all directions and a wild grin. I knew she wasn't my grandmother, since I had seen other pictures of my grandmother as a schoolgirl in the past. The frame was a particularly beautiful one.

"Who was she, Grandmother?" I asked.

I was surprised to see tears sparkle in my grandmother's eyes.

"Without that girl, I would never have the family I have today," my grandmother said. "Before I met that girl, I never made any friends. She was my best and only friend in middle school. We played so many otome games together. Oh, we had so much fun! That wild monkey of a girl met me when she fell from the top of a tree on to me. She nearly killed me with her buttocks! I am so glad that she did, because we became friends after that. She was the first person at school who knew my name. The wild monkey girl never stopped climbing trees ... she taught me how to grow plants, too, in her grandmother's garden. Just like you and me.

"If I never met that girl ... I don't think I would ever have had the courage to talk to your grandfather," my grandmother said. "I don't think I would have made any of my other friends. Yes. Because of that wild monkey girl, I am here today."

"What happened to her?" I asked. Perhaps they were still in touch ... or if they were not, perhaps I could try and find my grandmother's old friend. But those sad tears came back into my grandmother's eyes.

"Please, give me that photograph," my grandmother said. I handed her the frame and she sat and looked at her old friend, rocking up and down in the chair, stroking the cat all the while. The old lady with time-worn hands looked into the eyes of the young middle school girl.

"My friend ... my best friend ... she died young," my grandmother said. "There was a traffic accident. I will never forget the last message she left to me on my mobile phone ... 'Acchan, I can't clear the route of the black-hearted sadist prince!'"

I didn't understand what that message meant. My grandmother laughed even through her tears. "She stayed up all night playing an otome game we shared! My friend ... my poor friend. She didn't get enough sleep because of the game, so she rushed to school and had an accident. She couldn't win that black-hearted prince ... I hope that she somehow learnt the ending of that game in her afterlife."

My grandmother reached out and patted my hand. "I loved my husband and my family dearly, and I love you, my darling. I have had a wonderful life. But, as I reach the end of this life, my strongest hope is that I will get to be with that girl again in my next life. I hope to be at her side and grow old together this time. Two old women with cats on our laps, rocking up and down in a rocking chair in the sunlight, on a fine day just like today."

I was sad to think of that girl my age who had died so young, many years ago. She looked so excited and alive in her picture. I wished that she had lived to be my grandmother's friend at this age, and I would probably have known and liked her as well. Inwardly, I thanked the wild monkey girl for helping to make my grandmother the wonderful person she was.

I hugged my grandmother. "I hope that you get to see that girl again too, Grandmother. Now let me get you some more tea."

I wrapped a soft scarf around my grandmother's shoulders and went to get the tea things. She rocked gently, holding the precious photograph and looking out at her vegetable garden in the sunlight. These moments with my grandmother, I always treasured.