HashClue
What It Is
A physical cache is hidden at a real location. Inside it is a secret string. A SHA-256 hash of that string is published on Ethereum. The first valid on-chain submission of that string wins the pot.
That is the entire protocol.
What It Is Not
It is not a puzzle game. There are no riddles, no wordplay. Clues narrow the geography. They do not reveal the answer.
It is not cooperative. Other participants are competitors. They may watch where you search. If they see the string before you submit it, they can submit it first.
It does not promise equal outcomes. Participants with more money can buy more clues, make more guesses, and travel more easily. The protocol treats everyone identically but does not equalise resources.
How a Round Works
A round begins when a hash is published on-chain. At that moment a cache exists somewhere in the world containing the secret string. The hash locks it in. Nobody can change it afterward, including the person who placed the cache.
Clues unlock in a fixed order. Each costs a posted price in ETH. When someone pays, the clue becomes visible to everyone. You are not buying private information. You are buying public information earlier.
The clues narrow the geography. The first might tell you the hemisphere. By the fifth you might have a few hundred square metres. Even after all eight clues, billions of valid coordinate pairs remain. You cannot compute the answer. You have to go look.
Anyone can submit guesses at any time during a round. Each guess costs a fee that scales with the pot. Wrong guesses add to the pot. The string you submit is hashed and compared to the published hash. It matches or it does not. There is no partial credit.
When someone submits a matching string the round freezes. A verification window opens to check for protocol errors, not to judge the finder. If no errors are found, payout executes. 85% to the winner, 10% seeds the next round, 5% to charity.
A new round begins automatically.
What Winning Means
Be the first to submit the correct string at finality.
Finding the cache is not winning. Photographing the string is not winning. Only the on-chain submission matters.
If you find the cache and someone copies your string before you submit, they win. The protocol has no way to determine who discovered it first. Physical discovery is invisible to the chain.
Common Misunderstandings
Buying clues gives me an advantage. Clues are public. When you unlock one, everyone sees it. Your advantage is logistical, not informational. You can start travelling sooner. The person who never pays for clues still learns everything you paid to know.
I found it first so I should win. The protocol cannot see physical discovery. It only sees submissions. The first valid on-chain submission wins. If that feels harsh, you understand the protocol correctly.
The operator cannot cheat. After the hash is published, correct. Before the hash is published, the operator knows the string and could share it. This is disclosed. It is an irreducible trust assumption at the start of each round.
Clues eventually tell you the answer. Clues narrow the area. They do not eliminate the need to physically search. After all eight clues, over a billion coordinate pairs remain valid.
Guess fees pay for verification. Hash verification is computationally trivial. Guess fees exist to grow the pot and make brute force economically infeasible. You can verify candidate strings yourself before submitting.
The leaderboard shows who is winning. The Arena shows who has spent the most. It says nothing about who is close to finding the cache.
Where the Rules Live
The Protocol Constitution defines immutable principles and governance.
The Protocol Specification defines all mechanics, the string format, clue system, economic rules, and round lifecycle.
The Claim Verification Mechanics document defines what counts as a valid win.
The Status Feed announces significant protocol events shortly after they occur. It is not a marketing channel or hint system.
Everything else, including this page, is subordinate. When in doubt, read the specs.
For a walkthrough of the clue ladder and round lifecycle see How It Works. For risks, costs, and what you should understand before spending ETH see Before You Play.