Distilled from the FMZ digest article by 善, 'Analysing the Donchian Channel strategy in the research environment' (fmz.com/digest-topic/4385, section '买卖条件'). The article gives a complete rule set: upper band = highest high of the last N bars, lower band = lowest low of the last N bars, midline = their average. With no position, go long when the close is above the upper band and short when the close is below the lower band. Close a long when the close drops below the midline, and close a short when the close rises above it. None of the article's performance claims are used; our fee-inclusive backtest decides. Per L167 this is not a faithful port. It is the mechanism, restated. Stripped of instrument and timeframe, the mechanism is: 'enter in the direction of a close outside the N-bar high/low range; stay in until price gives back to the middle of that range'. It is a slow, flat-capable trend breakout, not mean reversion. It is also not an event-plus-fixed-clock trade (L166), because the exit follows the price state. Instrument choice: LINKUSDT.BYBIT perpetual on 4H bars. Bybit is at 1.4% of the corpus against a >=5% target, and its bar history goes back to 2021-03, about 5.5 years, unlike Hyperliquid (L168). The mechanism needs no supplementary feed, so the L160 ban on Bybit supplementary triggers does not apply. LINK is a liquid, high-trend-persistence alt that is outside the BTC concentration. The prior LINK death was a taker-flow contrarian signal, which is a different mechanism. The trade is single leg with no signal-on-A / trade-B (L143), no regime gate (L130) and no hand-typed universe (L151). There is one core parameter, the channel length N = 50 bars (about 8.3 days, as in the article's example), and the exit midline uses the same N. The declared flat state is the time between a midline exit and the next opposite-side close outside the channel; we expect to be flat about 50-60% of the time. Sizing: risk 2% of equity against the distance from entry to the midline at entry (the initial stop), notional = 0.02*equity / (|entry - midline| / entry), capped at 1.0x equity. Leverage is 1x, so there is no margin amplification. A long position is never flipped straight to a short. The position must exit at the midline first, which avoids the double-notional flip cost L150 describes.