A pinky promise (or "pinky swear") is a gesture in which two parties interlock little fingers in a symbolic gesture of agreement. What is the origin of this phrase?

One possibility, and probably the most straightforward one, is that it is an independent invention to describe an existing cultural practice of sealing promises by interlocking little fingers.

Another possibility, however, is that it originates from Japanese. Japanese sources frequently suggest that the English phrase "pinky promise" is a translation/adaptation of a similar Japanese concept called 指切り (yubikiri, lit. "finger-cutting") which supposedly has its origins in yakuza loyalty practices (if someone promised to do something and performed a yubikiri, and then broke their promise, their finger would be cut off).

However, as Wikipedia notes, this practice (if not the exact phrase "pinky promise") has been attested since 1860, as recorded in Bartlett's Dictionary of Americanisms. The Japanese yubikiri predates that1, so it's still possible that "pinky promise" derives from yubikiri, but I can't imagine there were many borrowings/translations from Japanese that long ago.

1 The Nihon Kokugo Daijiten, which is closest thing Japanese has to the OED, attests yubikiri in the sense of "a promise" from 1638, and in the sense of "cutting off a finger" from 1692.

  • 3
    I've never heard the phrase in my life (but then my dialect of English doesn't include the word pinky). But it seems wildly improbable that Japanese has anything to do with the phrase; and unless it does, I don't know what kind answer you are looking for. Most phrases in English (and in particular, phrases whose meaning is completely transparent) do not have an 'origin' that it is possible to point to,.
    – Colin Fine
    Commented Sep 3, 2013 at 23:33
  • @ColinFine I guess the question basically boils down to: is this phrase 1.) a borrowing, or 2.) not a borrowing, in which case it presumably originated independently in English. Does that seem like a reasonable question?
    – senshin
    Commented Sep 3, 2013 at 23:37
  • @Colin Fine - The Japanese are listed here: en.wikipedia.org/wiki/Pinky_swear and here: tvtropes.org/pmwiki/pmwiki.php/Main/PinkySwear
    – dcaswell
    Commented Sep 4, 2013 at 0:18
  • The first reference made above by @user814064 predates the opening of Japan by 10 years or so, and appears to have already been traditional in English at that time. From this, there is solid evidence that it originated independently in English, but it does not speak to the Japanese origin. What evidence is there that this predates 1870 in Japan? Commented Sep 4, 2013 at 2:25
  • Just a wild guess from me: There is this thing of "crossing fingers" while swearing to negate it. If you are doing a pinky swear using the hand with which you'd do the finger crossing, there is no chance for you to cheat. I just extrapolated this idea from the origin of clinking glasses, there is no proof at all.
    – skymningen
    Commented Sep 4, 2013 at 6:16

4 Answers 4


There's a Japanese and Chinese tradition called "red thread". Wedded couples tie a red thread on their pinky finger, because they believe that it was destiny that connects them together. The red thread signifies eternal togetherness. You use your pinky finger as a promise that you are never supposed to break.

From that tradition a popular kid's rhyme:





Which means:

Cut your finger and swear

Should you lie

Swallow a thousand needles

Cut your finger

So we see there is long standing traditions that were used in Japan to denote a truly high promise to the pinky. Then it became popular for the Japanese mafia used to cut off a finger if you did something they didn't like or lied them. Usually pinkies were the first to go. You can see this in some Japanese cartoons too.

This was brought to US from immigrants and movies. I am not sure where/when it became a "cute" thing to do. Because two people who did not know each other well would not pinky swear. Definitely alteration after acceptance.

  • 1
    Yes, that suggestion was mentioned in the question. What is the evidence for your assertion?
    – Colin Fine
    Commented Sep 4, 2013 at 9:27
  • @ColinFine - updated. Late night answers are shorter! Commented Sep 4, 2013 at 15:55

I can't offer any academic research, but my experience as a father is that this is the "little-girl" equivalent of a hand-shake. My daughter (now 21, but still my little girl of course) and her friends or her mom often make this gesture. I have always assumed that it was named from the action of interlocking pinkies rather than shaking hands. Seems much more likely than the alternative mentioned here.


Google Books search results for pinky promise, pinkie promise, pinky swear, and pinkie swear indicate that "pinkie swear" is the earliest of these four variants. Easily the earliest instance of any of the forms is from Don Appell, A Girl Could Get Lucky (1963), although it refers to a different gesture than the one familiar today, which involves two people interlocking their little fingers:

PENNY. I sure do. See that coffee table? I made it.

ANDY. Come on!

PENNY. Pinkie swear! (She kisses her pinky and lifts it skyward.) I mean, I didn't make the marble top. I had to buy that.


ANDY. Come on. You're making it up.

PENNY. No, I'm not! Pinkie swear! That's not the worst of it.

The next Google Books mention of "pinkie swear" is in Companies and Their Brands (1990), which notes the existence of a New York company called Pinkie Swears LLC. Six other instances appear between 1994 and 1997.

Pinky swear first appears in the Library of Congress's Catalog of Copyright Entries for July–December 1973, in a song titled "Pinky swear, I love you." Other early instances appear in 1983 and 1984.

The earliest Google Books instance of pinkie promise is from Betty Dorion, Melanie Bluelake's Dream (1995):

Melanie stood still. "Pinkie promise," she said, holding up her little finger. "We'll write each other every week."

Rachel curled her little finger around Melanie's. "Pinkie promise."

Instances of "pinkie promise" follow in 1998, 1998, 1999, and 1999, and 2000.

For the variant pinky promise, the earliest match is from 2000 in The Palimpsest Review.

The upshot of these results is that Google Books searches find many matches for one or another of the variants from about 1990 onward, but no relevant matches from before 1963. That 1963 match is interesting to me in several ways, including the unusual gesture made in expressing it, and the fact that it dates back to my childhood. I never heard pinkie promise (or pinkie swear) used until, I believe, the first Monsters Inc. movie (2001), which suggests that the term may have been regional, not national, in the United States during the earliest decades of its use.

  • 'pinkie promise' sounds mixed register to me, informal and formal at the same time. 'pinkie swear' is what I remember from childhood (1970's, South). Google ngrams shows a single instance of it from '63 (the instance you mention). Strange. Usually terms that pop out of nowhere are loan translations or inventions from newly popular media (book or movie).
    – Mitch
    Commented Feb 25, 2016 at 3:32
  • Strangely related.
    – tchrist
    Commented Apr 23, 2023 at 23:55
  • An instance of "pinky promise" appears in the San Fransisco Call of May 25, 1890. However the instance has nothing to do with little finger gestures. From "Apple Blossoms": "The dear old house that's on the farm / Is shaded on one side by trees / That in the autumn's breezy breath / Drops down the pippin apples free, / And one large tree its vigil keep / Beside the well with cooling shade, / Is filled with pinky promise sweet / Of juicy fruit that blossoms gave."
    – Sven Yargs
    Commented Apr 24, 2023 at 8:03

The word pinky comes from Dutch (Pinck) through Scots into English meaning something tiny. Pink eye meant the small slit left to see through, rather than the color of the eye (which, of course turns red). Pink is a small pink colored flower, from where we then get the name of the color pink. Pinking shears, for example, are small scissors. Young people are subject to the whims of their parents and so are sometimes incapable of fulfilling their oaths or don't understand the gravity of an oath. The Bible warns of making false oaths or leaving oaths unfulfilled as sinful. Therefore, children have long been forbidden to make oaths(eg. we still don't let them sign contracts). So, a "pinky swear" is a "small oath" or perhaps an oath by a small one -- up to the limits of what they can pledge. The addition of touching pinkie fingers is a natural follow-on from there, since both are "pinkies," and a little version of shaking hands on a promise as done by adults.

  • This sounds quite interesting, and plausible, but could also just be made up. Do you have have any references? Commented Feb 24, 2016 at 23:25

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