As children, we’re often taught that responsible people don’t break 約束 (yakusoku, promises).

Sometimes, though, simply saying 約束します (yakusoku shimasu, I promise) or 約束は破りません (yakusoku wa yaburimasen, I won’t break a promise) isn’t enough — there needs to be a ritual, a 指切り (yubikiri, pinky promise) to seal the deal. (The pinky, or little finger, however, is known as the 小指/子指 [koyubi] in Japanese.)

In Japan, a cheerful little tune often goes with such an action: 指切りげんまん嘘つたら針千本飲ます (yubikiri genman usotsuitara hari senbon nomasu).

The singsong tone of voice that’s used makes it really easy to overlook the 怖い (kowai, scary) vocabulary included in this 童歌 (warabe uta, children’s song). Let’s take a look at each one separately.

First is 指切り. While it means “pinky promise” here, when said in normal conversation you get: 指を切る (yubi o kiru, to cut off a finger).

The 拳万 (genman) is a bit harder to visualize, but it’s shorthand for 拳骨 (genkotsu, a fist) and 一万 (ichiman, 10,000). In other words, 一万回拳骨で殴ることを意味する (ichiman-kai genkotsu de naguru koto o imisuru, it means you’ll be hit with 10,000 punches).

Topping this severe list of consequences for 嘘をつく (uso o tsuku, lying) and going back on a promise is: 針千本飲ます (harisenbon nomasu, [I’ll make you] swallow 1,000 needles).

It’s no secret that children like to overexaggerate, whether in Japan or overseas. The rough English equivalent to this Japanese rhyme would be: Cross my heart, hope to die, stick a needle in my eye. Funny that needles play a part in punishment in both cultures.

So, if you’ve made a 指切り with someone, be sure to try and keep it.