Some women arrive on the Board with a bang. Kurumi arrived with an apology for being five minutes late, and has been quietly outperforming the bang ever since.

She's a second-year engineering student, which on the app is rarer than it should be, and her profile read like someone who'd been told to write one. Short, polite, nothing to hold on to. The thread was the same. I nearly didn't book the coffee, and then a gig moved and I had to ask her to shift it, and she shifted it without a flicker – no sulk, no "残念," a new time inside ten minutes. I've since learned to weight that kind of thing more than a good photo. At the time I just thought, well, that was easy.

The coffee was not easy, for the first quarter of an hour. She was nervous in the specific way of someone who's done this twice and thought about it two hundred times: hands round the cup, answers a beat too short, a laugh that arrived late. None of which matched the rest of her. She's a hundred and fifty centimetres of short skirt, knee socks and a labret piercing, a small steel stud under her lower lip, and she dresses like someone who decided a long time ago that the opinion of the carriage was not her problem. The nerves were about me, not about being looked at; she's plainly used to being looked at. I've learned to notice the one thing on a person that doesn't match the rest. It's usually where they live. I've met this before and the wrong move is to fill the silence. The right move is to talk about something that isn't her – the band, a terrible client, the Bristol accent – until she forgets to be careful. Around the ten-minute mark something gave, and she started talking a mile a minute – the course, the lab, a lecturer she couldn't stand, a band I'd never heard of – and didn't stop until the cups were cold. That was Kurumi. Sharp, funny, a bit fierce once the door was open, and utterly charming in a way that has nothing to do with trying.

Then she went home for two weeks, to wherever home is, and told me the dates before I asked. And somewhere in those two weeks she left the app.

I want to explain why that mattered, because on paper it's nothing. She didn't message me about it. I noticed because her profile suddenly had a 'this user has left the app' message and clicking it deleted it. Poof - no trace of her available on the app. But think about what it means: a woman a fortnight into this world, with a lunch booked with me and presumably a few other threads running, closed the shop. Whatever she came for, she'd decided she'd found enough of it. That's a costly move. Warm messages are free; anyone can send a heart. Surrendering your options with a first proper meal still on the calendar is a decision.

Lunch was sushi on a Friday in August, the day she got back. She was five minutes late and messaged in advance to say so, which is the whole Kurumi pattern in one line: under friction, she communicates. Same ten quiet minutes at the counter, same switch, same torrent. I've stopped worrying about the ten minutes. They're the price of admission. She was also, it turned out, unwell – a summer cold, flushed and apologetic and determined not to let it show – and I've never had a nicer lunch with someone who should have been in bed. We didn't drink. I still don't know if she does. I'll find out from the menu, not by asking.

Nothing has happened, in the sense the app means "happened." No ask, no hotel, no terms beyond the coffee-and-a-meal ones we started with. And since that lunch on the 7th we haven't met, for reasons that are nobody's fault and entirely ordinary: she went home for Obon, I went abroad for work, and at the start of September she went into hospital for a few days, which she told me about in the plain, unfussy way she tells me everything. No drama, no sticker storm. Just the fact, and the dates, and a "sorry, it'll be a while."

What there has been, every few days, all summer, is the thread. We take turns starting a conversation. She answers properly - a question back, a photo of whatever's in front of her, a complaint about the lab - rather than the two-emoji acknowledgement that means "I'm keeping you warm."