A twenty-something on the train home, phone propped on her knee, watching a two-hour film at 1.5x speed with the subtitles on. She has already read how it ends.
Ask her why she's rushing a movie she clearly wants to see, and she won't say she doesn't care about the story. She'll say one word, with total sincerity: taipa.
She means it isn't worth the time at normal speed. The film itself is not the point being measured. Her evening is.
コスパ is short for コストパフォーマンス, Japan's own compound built from the English "cost performance" — close kin to "price-performance ratio," a phrase that spent decades doing nothing more exciting than helping engineers argue about mainframes. The idea traces back to Herb Grosch's 1953 observation that computing performance rose roughly as the square of its cost, sharpened through systematic cost-versus-speed studies that researcher Kenneth Knight ran on computers from the 1950s and 60s, and settled into trade-press vocabulary by the 1970s, when vendors started advertising machines on their "price/performance" against IBM's. It was spreadsheet language, built for choosing between two boxes of circuitry.
Nobody can point to the exact day コスパ walked out of the IT department and into daily Japanese, but by around 2010 it was already so ordinary among students that a Nippon Express TV commercial that year could use the line "コスパで選んでる？" ("Choosing it by cost performance?") and expect everyone watching to get the joke instantly. コスパがいい means something — a bento, a haircut, a trip — gave you more than you paid for. コスパが悪い means you got fleeced. Dictionary editors now describe it as having fully earned its place in the language, no longer slang anyone has to explain.
Then, in 2022, the clipping went one step further. People started shaving パフォーマンス itself down to a single syllable, パ, and bolting it onto other nouns: タイパ, short for タイムパフォーマンス — whether something was worth your time. It became the No. 1 word on dictionary publisher Sanseidō's "New Word of the Year" list that November, propelled largely by a book published that spring, Toyoshi Inada's 映画を早送りで観る人たち ("People Who Watch Movies on Fast-Forward"), which documented young viewers speeding films up, skipping scenes with no dialogue, and reading spoiler sites beforehand — not out of impatience, exactly, but because watching at normal speed had started to feel like a bad trade.
Sanseidō's own editors said what struck them was the clipping itself — パフォーマンス reduced to one sound, パ — and compared it to how Japan's Pacific League of professional baseball became, decades ago, simply パ・リーグ, calling it the boldest abbreviation of its kind since. Once the suffix was loose, more of it followed: メンパ, mental performance, for protecting your own patience and energy — buying a ready-made side dish rather than cooking one from scratch, so dinner costs less of you. Industry surveys, modest in scale but consistent in direction, back up how far this has spread: one poll of young single adults found roughly seven in ten said both cost and time efficiency shaped how they live, and a separate Gen Z survey found hobbies and entertainment were the one category everyone agreed was worth spending real time and money on, performance ratio be damned.
English never let "cost performance" leave the spreadsheet. It is still, mostly, what an IT department says when choosing between two servers, and almost nobody utters either word about their lunch. Japan took that narrow, bloodless metric for comparing machines and pointed it at being alive — then built a small factory out of the leftover syllable, so that money, time, and now mental energy can each be weighed on the same one-sound scale. English has a quiet phrase for pricing a server. Japan built a suffix for pricing everything else, including whether your evening is worth sitting through at normal speed.