How Yoko works

Yoko is a prediction market on Bittensor. Each market is a bout: a yes-or-no question about a subnet metric, measured at a fixed Subtensor block. Back EAST if you think the answer is YES, back WEST if you think it is NO. When the bout is settled, every winning share pays 1 TAO.

Everything runs on smart contracts on Robinhood Chain, and every bout is denominated in TAO. On mainnet the collateral is TAO bridged to Robinhood Chain.

A bout is fixed the moment it is created. Its question (one of four metrics, a subnet, a threshold and a target Subtensor block) is hashed on-chain, so nobody can change it afterwards.

1. 壱

   The card

   The bout is created and listed. Its odds start at 50/50.

2. 弐

   The odds

   Anyone can back EAST or WEST, or sell their shares back, until the bell.

3. 参

   The bell

   Trading closes at the bout's closing time. No trade is possible after it.

4. 肆

   The call

   Once the target block exists, the result is computed from public Subtensor data, posted on-chain, and can be challenged for 24 hours before it becomes final.

Prices come from an automated market maker (a logarithmic market scoring rule, LMSR). A price is the market's implied probability: if EAST trades at 62%, the market gives YES a 62% chance. EAST and WEST always add up to 100%.

There is always a counterparty. You never wait for another trader: the market maker quotes every trade, and the house stands behind it.

• Back: buy shares of one side. Each share pays 1 TAO if that side wins.
• Lay off: sell shares you hold back to the market, at any time before the bell.
• Every quote is read from the bout's own contract and priced by the same code as the trade itself, so what you see is what you pay.
• You sign a 1% slippage bound. If other trades move the price more than that before yours is mined, your transaction reverts instead of filling at a worse price.

Trading fee

2% of the trade (each bout keeps the fee it was created with; capped at 10%)

Where fees go

70% to the house (seeders), 30% to the protocol

Liquidity (b)

Sets a bout's depth: a larger b means a smaller price impact and a larger worst case for the house. Testnet bouts use b = 500 TAO.

After the bell, once the target block exists, the reporter computes the result from Subtensor data and posts it on-chain together with the hash of an evidence document and a link to it.

The metric is not read at a single block, which would be cheap to manipulate. It is measured over the 7,200 blocks up to the target block (about one day), from hourly snapshots, around 24 of them. If too many snapshots are missing, the metric is declared unresolvable: Yoko never guesses from a neighbouring block.

Challenge window

24 hours after the result is posted

Challenge bond

10 TAO by default, never less than 1 TAO

Who rules a challenge

The guardian, a multisig. It sets the final result and decides whether the bond is returned to the challenger or kept.

If the guardian stays silent

7 days after the window closes, anyone can end the challenge: the bout is voided and the bond is forfeited

If the reporter stays silent

3 days after the bell, the guardian can resolve the bout itself

Finality

A bout's result is set once and can never change afterwards

Every result links to its evidence document. The Review the call page of each bout fetches that document, recomputes its keccak256 hash in your browser and compares it with the hash committed on-chain. If they match, the result on-chain is exactly the one in the evidence, and the evidence carries the raw Subtensor data the metric was computed from.

• YES or NO: each winning share redeems for 1 TAO. Losing shares pay nothing.
• Void: every share, YES or NO, gets the same refund: the bout's collateral divided by all shares outstanding. The refund does not depend on what you paid, so a share bought cheaply can come out ahead and one bought expensively behind.
• You collect your payout from the bout page once the result is final.

One shared vault, funded by seeders, is the counterparty to every bout. Its risk is not a promise: it is bounded by the market maker and reserved in advance.

Worst case per bout

b × ln 2, reserved when the bout opens (about 346.6 TAO for b = 500). The house can never lose more than this on a bout.

Coverage ratio

Total assets ÷ reserved liability. Above 1×, the house covers the worst case of every open bout at once.

Reserve floor

10% of total assets stays locked (governance can raise it to 50% at most). A withdrawal that would cut into reserves or the floor is refused.

Trader funds

Held by each bout, never mixed into the vault.

Seeding: deposit TAO and receive shares of the vault. Seeders earn 70% of trading fees and whatever a settled bout leaves over after winners are paid, and they cover a bout's shortfall when winners are owed more than it holds. Vault shares can be worth less than what you deposited.

Emission share

Will subnet N hold at least X% of emissions? Its emissions summed over the window, divided by the sum for all subnets.

Emission rank

Will subnet N rank R or better by emission? Ranked by summed emissions; ties go to the lower subnet number.

Stake

Will subnet N hold at least X TAO staked? The average TAO in its pool over the window.

Top N

Will subnet N be among the top N subnets by emission over the window?

The root network (subnet 0) is never counted. Yoko only lists questions settled by the whole market's staking behaviour, never by a decision a single team controls.

• You can lose everything you put into a bout. Shares on the losing side pay nothing.
• The contracts have been reviewed internally but not yet externally audited. Mainnet waits for that audit.
• On testnet, TAO is a test token with no value.
• Results depend on the reporter and the guardian (see The call) and on the Subtensor data source. If the data is missing, a bout can end up void.
• If a void becomes foreseeable while a bout is still open, its trading can be paused.
• Seeders can lose up to the reserved worst case on every open bout.

1. 壱

   Why can't I connect my wallet on my phone?

   Open Yoko inside your wallet app's built-in browser (MetaMask and most mobile wallets have one). Connecting from Safari or Chrome directly is coming.

2. 弐

   Can a result change once it is final?

   No. A bout is resolved once, and the contracts refuse any second resolution.

3. 参

   Where do the numbers in the app come from?

   From the contracts themselves. The house's figures are direct reads of named vault functions, each with a link to the block explorer, and odds are computed from each bout's on-chain state.

4. 肆

   What does the house earn?

   70% of every trading fee, plus what settled bouts leave over after paying winners.