As avid anime watchers and JRPG players will already know, Japan is the master of the sentimental story. The cycle of obligation, failure, regret and determination spins so effortlessly through Japanese stories that it's almost familiar, yet still somehow manages to wind its way into your heart before you know it's begun.

As exhibit A, take Kana Uemura's 2010 hit, Toire no Kamisama (Goddess of the Toilet). As ridiculous as this may sound, it's not an ad for some kind of domestic cleanser: It's a 10-minute acoustic elegy for her grandmother, delivered in possibly the sweetest Kansai accent you'll ever hear.

From the third grade, for whatever reason,
I lived together with my grandma.
It was right beside my real home home,
But I spent my days with grandma.

I helped her every day
And we played gomoku together.
But I didn't like cleaning the toilet,
So grandma had this to say:

"In the toilet, well you know, you know,
There's a beautiful goddess in there.
So if you make it beautiful every day
You'll become as beautiful as a goddess, too."

From then on, Uemura naturally commits herself to keeping the toilet clean every day. (Gomoku is a board game played with black and white go pieces, where the goal is to get five pieces of your color in a row.)

The story, however, doesn't end there. They have their ups and downs, and as Uemura gets older, she and her grandmother begin to fight. She eventually stops going home after school, choosing to spend time with her boyfriend instead.

She finally moves to Tokyo, and within two years, her grandmother is hospitalized. When Uemura goes to visit her at last, she finds her weak and thin. They speak only briefly, and her grandmother passes away the next morning.

Uemura wonders if grandma had held on waiting for her to visit, and laments never having been able to offer anything in return for having raised her. She ends the song with "Obaachan, arigato" ("Thank you, grandma") and says she cleans the toilet until it sparkles every day.

Toire no Kamisama sold some 137,000 physical copies in addition to over 500,000 downloads in 2010, reaching No. 1 on both the Oricon singles charts and the Billboard Japan Hot 100. It inspired two books by Uemura—an autobiography and a picture book—as well as a two-hour TV drama. It remains her only major hit to date.