What was this purchase for?

The other question

The last chapter ended with every purchase counted exactly once. That settles how many. It says nothing about what. Look at what actually reaches a ledger:

Four real purchases: an online order, a taxi, a week of groceries, a subscription. You would recognise every one of them if you had been there. Your statement does not tell you which is which — and a budget cannot use a line until somebody has answered the question this chapter is named after: what was this purchase for?

Why a name is not enough

Here is one of mine. On a Sunday morning in Seoul I bought an Americano at Starbucks. The moment I tapped my card, my phone buzzed with a text from the card company, and a few weeks later the same ₩4,900 turned up on my statement. This is everything the bank told me about it:

Neither of them says coffee. Neither says Starbucks. A week later, looking at ₩4,900 paid to “SCK Company Co., Ltd.”, I had no idea what I had bought.

That is not bad luck; it is how statements work. Shop names are written for banks, not for people. They get shortened to fit a field (NTUC FP is NTUC FairPrice, a supermarket). They name the payment company instead of the shop (KG INICIS takes payments for thousands of Korean websites). And the same letters can mean different things in different countries — NTUC FP paid in Singapore dollars is a supermarket; the same token anywhere else means nothing at all.

Then there is the second half of the answer: yourcategories. One household files coffee under “Dining out”, another under “Treats”, a third has a “Café” line of its own. Knowing that a shop is a café is only useful once you know where cafés go in this household.

Who knows best, asked in order

Aurora answers the question by asking the people and sources that know, starting with the one that knows best, and stopping at the first good answer:

1. 1YouA rule you made — “Remember for this shop” — always wins. Nobody knows your spending better than you.
2. 2Aurora's merchant libraryWell-known shops, by country: the supermarket chains, taxi companies, airlines and streaming services that everyone pays.
3. 3Other households, togetherWhen at least three unrelated households independently file a shop the same way, it becomes known. Only “this shop, in this country, is a supermarket” is shared — never a person, an amount or a date.
4. 4Aurora's own memoryWhen the AI was sure about a shop before, that answer is kept, so the same shop never needs asking again.
5. 5The AI, in your wordsFor a shop nobody has seen, the AI reads the line and places it in one of your own categories, using the names you chose.

The order matters more than it looks. A clever guess should never overrule something a person decided, so the cheapest source is not asked first — the most trustworthy one is.

Your categories stay yours

Two promises sit underneath all of this, and they are worth saying plainly.

When it isn't sure, it asks

Most lines are filed without you. The ones that are not wait in one place, marked Needs review, each with the reason in words:

Three honest reasons: nobody could tell what it was; the AI had a guess but not a confident one; or the amount is far from what you usually pay there (worth a look — it might be a mistake, or a month of shopping in one go).

Notice what is not on the list. A shop you have never used before is not, by itself, a reason to stop you. If you live between countries, almost every shop is new for a while — and a review pile full of perfectly ordinary purchases teaches you to ignore it.

Answer once, and it stays answered

When you pick a category for a line, Aurora offers to Remember for HAPPY MART 24. Say yes, and that becomes step 1 on the list above: next month's HAPPY MART lands in Groceries with nobody asking. Every rule you make is listed in Settings → Rules, where you can change or delete it.

This is why the pile shrinks instead of growing. Your life repeats — the same supermarket, the same commute, the same subscriptions — so the questions repeat too, and each one only needs answering once. What is left after a few months is mostly genuinely new: a trip, a one-off, a shop that opened last week.

The receipt knows more than the bank

Back to my coffee. On the way out of the shop I took a photo of the receipt, and the receipt said everything the bank could not:

STARBUCKS. One Americano. ₩400 off for bringing my own cup. ₩4,900 paid — the same figure as the card text. Aurora recognised the two as one purchase (the pairing from Chapter 10), joined them into a single row, and took the name and the category from the receipt. Weeks later, the statement's “SCK Company” joins the same row instead of starting a new mystery.

That is the general rule. A statement line knows a shop; a receipt knows what was in the bag. So when both describe the same purchase, the receipt has the better claim on what it was for — and, unless you picked a category yourself, the receipt's is the one that stays.

And when one receipt holds several kinds of thing — groceries, a phone charger and a bottle of shampoo from the same online order — the items can go to different categories, the way Chapter 7 showed with the supermarket bill.

Your journey so far