This post discusses key story points of Code Geass R2 and season 1 of The Apothecary Diaries.
Two characters face each other and hook their little fingers together. Then they chant something in unison.
You may have seen this in anime. It's called yubikiri, a Japanese way of making a promise, and it looks a lot like a pinky promise.
But translate the words they're chanting, and you might be surprised:
"If you break this promise, I'll punch you ten thousand times. I'll make you swallow a thousand needles."
A cute gesture, paired with some very violent words. There's a reason for the combination.
How yubikiri works, and what the words mean
Two people hook their little fingers together, shake them gently up and down, and chant:
Yubikiri genman, uso tsuitara hari senbon nomasu, yubi kitta.
Let's go through it word by word.
- Yubikiri: literally, "finger cutting"
- Genman: written with the characters for "fist" and "ten thousand". Ten thousand punches
- Uso tsuitara: "if you lie", that is, if you break the promise
- Hari senbon nomasu: "I'll make you swallow a thousand needles"
- Yubi kitta: "the finger is cut". On these words, you let go of each other's fingers
The "thousand" isn't meant as an exact number. It just means a huge amount. There's also a reading in which harisenbon refers to the porcupinefish, a fish covered in spines, which is called harisenbon in Japanese.
Why is it so violent?
According to Japanese reference dictionaries, yubikiri goes back to a custom in the pleasure quarters of the Edo period (1603–1868). A courtesan would cut off her own little finger and give it to a client as proof of her vow.
Over time, this turned into a gesture where two people simply hook their little fingers together, and it spread among children. The threats of ten thousand punches and a thousand needles are said to have been added later, as the penalty for breaking the promise.
Yubikiri in Japan today
Today, yubikiri is mostly used for promises between children, or between parents and children. "Let's play again tomorrow." "Okay, once you finish your homework." Small, everyday promises.
Of course, nobody actually makes anyone swallow needles. Everyone knows it's a joke.
Still, chanting such frightening words in a cheerful voice says something: this isn't just a casual promise. You could say the cute gesture carries the feeling, and the violent words carry the weight of the promise.
Hunter x Hunter: a child leaving home, and the woman who raised him

In episode 1 of the 2011 Hunter x Hunter, twelve-year-old Gon is about to leave the island where he grew up, to become a Hunter like his father.
Before he goes, Gon makes a pinky promise with Mito, the woman who raised him.
This is yubikiri in its most typical form: a promise between a child and the adult who brought them up. Two people about to be separated use their little fingers to confirm that even apart, we're still connected.
Placed at the very start of a story about leaving home, that pinky promise reminds us that however big Gon's adventure becomes, he still has somewhere to come back to.
Code Geass R2: one little finger is enough to bring a promise back

A pinky promise isn't always just child's play. It can also stand for a promise kept over many years.
In episode 9 of Code Geass: Lelouch of the Rebellion R2, "The Bride in the Vermillion Forbidden City", a flashback shows a pinky promise between the young Empress, Tianzi, and Xingke, a man whose life she once saved. Tianzi has never once set foot outside the Forbidden City. One day, he would take her out into the world. That was their promise.
To keep it, Xingke became a military officer and stayed by her side. Then comes the day of a political marriage she never wanted. And Tianzi raises the hand that made that promise.
No words are needed. Just showing that little finger brings a promise from years ago back to life between them.
A yubikiri becomes a signal only the two of them understand. This scene shows how powerful that can be.
xxxHOLiC: when promises get too heavy
xxxHOLiC turns the violent side of the chant into a story, in episode 9, "Pinky Promise".
A young woman whose finger has gone numb comes to a shop that grants wishes. She turns out to be someone who has made countless pinky promises.
Even promises made lightly grow heavy when they pile up. Once you know that the yubikiri chant is really a promise of punishment, you can feel why this episode is unsettling.
The Apothecary Diaries: what yubikiri originally meant

And the anime that brings back yubikiri's original meaning is The Apothecary Diaries. Season 3 is airing this season.
The tip of the little finger on Maomao's left hand is slightly missing. In season 1, episode 23, "Balsam and Wood Sorrel", the reason comes out. Her mother, Fengxian, a courtesan, had sent her own finger, and a piece of baby Maomao's finger, to Maomao's father, Lakan.
A courtesan cutting off a finger and sending it as proof of a vow. That's yubikiri as it was before it became a children's gesture.
Behind the cute gesture lies a much heavier history. Knowing it may change how you see the next scene where two little fingers meet.
When little fingers meet, the promise isn't light
When an anime character makes a pinky promise, it's not a vague, maybe-someday promise.
It may be proof that two people stay connected even when they're apart, like Gon and Mito. It may be a vow kept for years, like Tianzi and Xingke's.
And in a story, whether that promise is kept or broken often shapes what happens later.
So next time you see two little fingers hook together, pay a little attention to what exactly they're promising.
More on Japanese customs through anime: omamori and other wish charms, why first names make characters blush, tsukkomi, boke and why yelling is funny.
Sources and notes
- Origin of yubikiri, genman and hari senbon: National Diet Library Collaborative Reference Database (based on Nihon Minzoku Daijiten and other reference works)
- Hunter x Hunter (2011) episode 1: Nippon TV official synopsis
- xxxHOLiC episode 9: xxxHOLiC Wiki
- The Apothecary Diaries season 1, episode 23: official site
Names are written given name first, as they usually appear in English releases.
