For the curious — how the tide decides
The tide is Blake's testnet4 — the BLAKE2b hardfork of Bitcoin, which parted from
plain testnet4 at block 150,308. From there a header is 164 bytes and a block hash is
BLAKE2b rather than double-SHA256, and
mempool.guide is
the explorer that follows it. Which chain matters to the proof: above the fork the same
height names a different block on plain testnet4, so check a race on Blake or you will be
comparing against another chain's history.
In Tide mode your bet names a Blake block that does not exist yet.
When that block is mined, the race seed is sha256(blockHash | mark) — your
mark is a random nonce fixed at bet time. The seed picks a number on a 10,000-point
line; each boat owns a band of it sized by its odds. Nobody — not you, not this page, not
anyone — knows the winner before the tide comes in, and anyone can recompute it afterwards
from public chain data. The verify ✓ in the log does exactly that, in your browser.
Races settle only after the deciding block has a confirmation on top of it — testnet4
reorgs are real (we watched one orphan a race's block), and if a deeper reorg ever moves
a settled block, verify says so instead of pretending. Races logged before the fleet moved
to Blake are marked as the plain-testnet4 races they were, and still verify against the
chain they settled on.
Even the race replay is honest: every gust and stall is drawn from the same seed, so two
replays of the same race are identical, anywhere.
Practice mode is seeded locally and marked as such — instant, but not provable.