Two honest wallets, the same twelve-word seed, different balances on the screen. Neither is defective, and neither is lying. They are looking at different branches of the same tree, and the number that decides which branch is the first in the derivation path — the so-called purpose, which the previous lesson left open.
There are four purposes in use, and each corresponds to an address format. The 44 is the oldest, proposed in 2014 by Marek Palatinus, and generates addresses that start with 1. The 49 generates those that start with 3. The 84 generates the bc1q. The 86 generates the bc1p, from Taproot. Four numbers, four families of addresses, all born from the same phrase and none of them communicating with the others.
The order in which they appeared tells the story of Bitcoin itself. The 44 is the original form: public key, two hashes, one address. It has worked since 2009 and continues to work, but it takes up more space in the block — and block space is what the fee pays for, as the beginner track showed. An entry in this format occupies about twice what a modern entry does, and this difference fully appears in the fee you pay.
The 84 is the format that solved this in 2017 when SegWit went live. The signature stopped counting as the rest of the transaction does, and an entry that cost one hundred and forty-eight weight units started costing around sixty-eight. The address became longer to read, all in lowercase, starting with bc1q — and cheaper to spend.
Between the two is the 49, which is a transitional piece and deserves to be understood as such. In 2017, an old wallet didn't know how to send money to a bc1q address; it simply refused. The trick of the 49 was to wrap the new address inside an old format, the one that starts with 3, which any wallet had accepted since 2012. The recipient paid less to spend later, and the payer didn't need to update anything.
The 86 is the most recent, from 2021, and uses Taproot. It saves a bit more and, mainly, makes simple spending and complex contracts indistinguishable on the blockchain — which is a topic for another module. Today, the four families coexist, and that's why some wallets show four accounts on the same screen: they aren't four wallets, it's the same seed viewed through four paths.
This is where the diagnosis of the missing balance comes from, which is almost always the same story. You created the wallet in an app that used 84, received there, and then restored the twelve words in an app that assumes 44 by default. The coins remain exactly where they were, visible to the entire world on the blockchain, under addresses that the second wallet never calculated because it was looking at the branch next door.
The fix is procedural, not luck. Note down with the seed which wallet created it and which path it used — a line on the same paper solves the problem before it exists. If it's already too late, restore in a wallet that offers the choice of path and test all four, or use the account's xpub in a block explorer to see the history without typing any key. And remember the limit of twenty unused addresses from the previous lesson: sometimes the branch is right, and the sweep just stopped too soon.
A warning worth more than the rest of the lesson: this investigation is never done by pasting the twelve words into a site that promises to find the balance. The site that finds your money is the same one that takes it, and the beginner track has already described this scam in detail. Serious recovery tools run on your machine, preferably disconnected from the internet.
There is still a way for the same seed to generate a wallet that none of these four paths find, and it is not an accident — it is deliberate protection, chosen by the user. In the next lesson, the passphrase, the thirteenth word.