Nineteen years old, negotiated me up before we'd met, refused to send a photo, and then left the app before I could find out whether any of it was justified. Kei is the shortest entry on the Board and the one I think about more than I should.

Her profile was ordinary. Her messages weren't. Where most nineteen-year-olds on the app write in stickers and let you set the terms, Kei asked what mine were, read them, and came back with a number. Not a tantrum, not a sulk – a counter. My standard for the thing the app calls 大人 was five. She said seven, and gave a reason, and the reason was coherent, and I sat there on a train reading a negotiation from a teenager that was better-structured than most I've had with procurement departments.

I asked, as I do, for a photo before the coffee, since her profile had none. She said no. Judge me at the coffee. Five words. On an app where every woman's opening move is a filtered selfie, a nineteen-year-old declining to be pre-screened, and telling me so in the imperative, and asking me to do the judging in person, was either the most confident thing I'd read all summer or the biggest red flag. I couldn't tell. I still can't. I booked the coffee.

She left the app before it. No message, no cancellation. Just the grey frame and the word 退会済み where a person had been. Whether she found what she was looking for, or was never going to show, or was never nineteen, or never Kei, I'll never know, and I notice that's true of most of the women who've left the app, and that I only mind about this one.

What she left me with is a rule I hadn't had before: the ones who negotiate are the ones worth having, and the ones who negotiate before the coffee are the ones who understand it's a market. Kei knew her price and held it. Everything about the thread said she'd have shown up on time and told me what she thought of the café. Everything about the grey frame says the thread was all there was.

Seven, and no photo, and a coffee that never happened. I'd have paid it.