How to play
Chaindoku rules
Chaindoku is a sudoku-style logic game where every grid tells an investigation on the blockchain. An address has been drained and several suspects circle around it: place each one back on the grid, then unmask the culprit. Everything is solved with logic, never by guessing.
How it works
Three steps, no crypto knowledge needed
Treasurer
Victim
The treasurer of a small DAO signed a suspicious transfer, then vanished. Four addresses are involved, only one betrayed him.
1A theft has happened
Every case opens with a briefing: a drained treasury, a victim, a handful of suspect addresses.
Miner
He signed in block 1.
Treasurer
He signed before the Anon Dev.
2Every suspect leaves a clue
Signing block, depth of the flow, zone crossed: the clues tell you where each one can stand.
- Culprit
3Unmask the culprit
Place each suspect, one per row and column, like a sudoku. The one sharing the victim's zone is the culprit.
The grid
- Columns = blocks (B1, B2…): the chronological order of signatures, left to right. Signing before someone means being in a block further left.
- Rows = hops (H1, H2…): the depth of the fund flow, top to bottom. A shallower hop is higher up.
- Colored zones = clusters (Vault, CEX, DEX…): groups of addresses. Each zone's name is written below it.
- Symbols (RPC node, mixer, rug pull…): markers placed on some cells, named in each case's legend.
The golden rule
- There are as many suspects as rows. Each one holds a single cell.
- Exactly one address per row and one per column, as in sudoku.
- No address on a hatched cell: it never existed.
The clues
- Each suspect card gives a clue about where they stand. Every clue is true, and every clue is needed.
- The general constraints apply to the whole grid.
- A numbered gap is exact: “two blocks after” means two columns to the right, no more, no less. Without a number, “before” or “shallower” means anywhere to the left or higher up.
- Adjacent means touching by a side (not diagonally).
- Being labeled Vault means standing in the Vault zone. Being a dormant address means standing on the cell with that symbol.
The culprit
- Once the grid is complete, the culprit is the only address sharing the victim's cluster.
Levels
- Every case is checked by a solver: a single solution, and every clue counts.
- In Easy and Medium, everything can be deduced, with no hypothesis at all.
- In Hard, you sometimes have to try a cell and see that it leads to a contradiction: the number of these hypotheses is shown on the case.
Tools
- Tap a suspect card to select it, tap a cell to note a lead, and hold to place the suspect there.
- Block crosses out a cell once you know nobody can stand there, Undo takes back your last move, Erase clears a cell.
- Hint: if you're stuck, it shows you where to look, then why, then the cell. Its reserve refills as you play, and a game with a given cell doesn't count toward your record.
Investigation method
- Start with direct clues: “he signed in block 5” fixes a column, “she is labeled CEX” fixes a zone.
- As soon as a suspect is placed, their row and column are taken for everyone else.
- Then combine the relative clues (before, shallower, same cluster) with the suspects already placed.
- Stuck? Look for the row, column or zone with only one possible cell left.
Rules that come from on-chain investigation
These words are not just scenery: real investigators date transactions by blocks, count hops from where the funds started and group addresses into clusters. Chaindoku turns that into a grid.
Understand on-chain investigation →Ready to investigate?
The guided tutorial takes two minutes, and the Initiation chains five short lessons. Then on to the cases.