# PINCH-STAKE-1 (revision 2) — Stake-gated, tiered mining

Status: deployed on the public nodes; active from mainnet block 20,000. Node: core-geth v1.13.0 (commit 85093c85) + `pinch-stake.patch`, released as `1.13.0-pinch.3`.
Decisions (project owner, 2026-11-05): hard threshold below which blocks are invalid; above it the reward grows with the balance; the 210M schedule is kept. Revision 2 (same day, before activation): the threshold grows with supply instead of starting at a fixed 25,000 PINCH.

## Rule (from the activation block, Pinch networks only)
1. **Threshold.** T(n) = min(25,000 PINCH, 0.25% × S(n)), where S(n) is the sum of scheduled block rewards for blocks 1..n (uncles excluded). T depends only on the block number. A block is valid only if its coinbase holds at least T(n), measured after the block's transactions and before any reward is credited.

| Block | S(n) | T(n) |
|---|---|---|
| 20,000 (activation) | 1,000,000 PINCH | 2,500 PINCH |
| 100,000 | 5,000,000 PINCH | 12,500 PINCH |
| 200,000 and later | ≥ 10,000,000 PINCH | 25,000 PINCH (cap) |

**Scheduled vs actual supply.** S(n) is the scheduled supply from the reward schedule alone. Actual supply differs: it is lower once reduced tier rewards are paid, and before block 20,000 it is higher by the uncle rewards minted then (20 uncles and 906.25 PINCH up to block 11,023; the final figure is fixed at activation). The threshold always uses S(n).

2. **Tiered reward.** Reward = scheduled reward (50 PINCH today, halving every 2,100,000 blocks) × tier fraction:

| Coinbase balance | Fraction | Reward in the first era |
|---|---|---|
| < T | — | block invalid |
| ≥ T | 50% | 25 PINCH |
| ≥ 4·T | 60% | 30 PINCH |
| ≥ 8·T | 75% | 37.5 PINCH |
| ≥ 20·T | 100% | 50 PINCH |

3. **No uncle rewards.** After activation uncle rewards and the nephew bonus are not paid. Uncles stay valid and still count for difficulty. A block therefore never mints more than the scheduled reward.
4. **Supply cap.** Post-activation issuance is at most the 210,000,000 PINCH schedule. The only amount above the schedule is the uncle rewards already minted before block 20,000 (Ethash pays those on top of the block reward); that figure is fixed at activation and published then (a few thousand PINCH at most, under 0.002%). The unpaid part of every reduced reward is never minted.
5. **Scope.** Only chain IDs 5261646 (mainnet) and 5261647 (test). Other chains are unaffected.

## Activation
- Mainnet: **block 20,000**. Every node and miner must run `1.13.0-pinch.3` before that block (pinch.1 and pinch.2 were pre-activation candidates and must not be used). A node left on the old version follows a separate chain after the activation block.
- Test chain (5261647): block 30. The old public testnet is retired; the new version does not validate its history.

## Implementation
- `params/mutations/pinch.go`: constants, tier table, `PinchStakeCheck`, reward scaling.
- `params/mutations/rewards.go`: `AccumulateRewards` applies the tiered reward and zero uncle rewards after activation.
- `eth/tracers/api_parity.go`: `trace_block` reward entries show the amount actually credited (derived from the block's final state via `PinchMinedReward`) and zero for uncles.
- `core/state_processor.go`: threshold check while importing a block (invalid block → rejected).
- `consensus/ethash/consensus.go`: a miner below the threshold does not assemble a block (no wasted work).
- `go.mod`: three `replace` lines pointing at a deleted repository were dropped (build only, no consensus effect).
- Tests: `params/mutations/pinch_test.go` (tiers, gate, halving, uncles, per-block issuance bound, reward derivation, other chains) and an independent review with extra tests (`pinch_extra_test.go`, `CODEX_REVIEW.md`). Existing `core` and `consensus/ethash` test suites pass. A 3-node local test (patched miner, patched verifier, unpatched miner) passes 9/9.

## Notes
- New miners need the threshold amount (2,500 PINCH at activation, rising to at most 25,000) on their reward address before they can mine.
- Several machines may mine to the same address (pool style); the tier depends on that address's balance.
- Public texts describe the rule neutrally; no price, return or listing promises.