當今天交易的最低價高於昨天的最高價或今天交易的最高價低於昨天的最低價，缺口即形成。
當後來的價格走勢越過該缺口時，表明該缺口被回補。
有兩條基本的原則：
1. 避免普通缺口；
2. 在缺口被交易量確認之後再交易（等量成交圖突出了價格和交易量之間的關系）。
普通缺口
普通缺口出現在沒有明顯價格走勢的市場中。缺口出現後不會出現新高或新低，並很快會被下面的價格走勢回補。
下面事件導致的缺口應該被忽略：
• 價格根據應付紅利調整時出現的除息缺口；
• 新股發行時的缺口；
• 期貨合約到期日的缺口。
突破缺口
突破缺口通常伴隨著高交易量，而且發生在價格突破交易區間之後。它們之後通常會出現新高或新低，回補的概率很小。
交易策略：上升趨勢中的突破缺口，在突破後做多並在缺口的下方止損；下降趨勢中出現突破缺口後做空並在缺口上方止損。
持續缺口
持續缺口出現在一段很強走勢的中部位置，可以有效的預測趨勢的幅度。它們也會伴隨這新高或新低，這一點和衰竭缺口有所區別。持續缺口通常不會被回補。
交易策略：如果交易量很大（至少大於50%），交易方法類似於突破缺口。提前進場，等待新高或新低來確認價格走勢。如果新高或新低沒有出現，那麼立刻平倉——它有可能是衰竭缺口。
衰竭缺口
衰竭缺口出現在一個很強走勢的末端，是大趨勢衰竭之後的最後一次漲，通常伴隨著大的成交量。它們和持續缺口的區別是，衰竭缺口完成後價格不會出現新高或新低，並將很快被回補。
交易策略：上升趨勢中出現衰竭缺口，做空或平掉多頭頭寸；下降趨勢中的衰竭缺口，做多或者平掉空頭頭寸。
島形反轉
島形反轉是衰竭缺口出現之後，突破缺口在相反方向出現的一個很強的反轉信號。它的交易策略和衰竭缺口一致。
Gaps
Gaps occur when the lowest price traded is above the high of the previous day or, conversely, when the highest price traded is below the previous day's low.
A gap is filled when the range of subsequent bars closes the gap.
There are two basic rules:
1. Avoid trading common gaps, and
2. Only trade gaps when they are confirmed by volume.
Equivolume charts highlight the interaction of price and volume.
Common Gaps
Common gaps occur in markets without a strong trend. They are not followed by new highs or new lows and are quickly closed in subsequent days' trading.
Some gaps are caused by events and should be ignored:
• Ex-dividend gaps occur as price adjusts on the day after a dividend becomes payable;
• New share issues; and
• Expiry of futures contracts.
Breakaway Gaps
Breakaway gaps are normally accompanied by heavy volume and occur when prices break out of a trading range. They are usually followed by a series of new highs in an upside breakout or, a series of new lows in a downside breakout, and are seldom closed.
Trading Rules
Upside Breakaway
If the gap is accompanied by heavy volume, go long and place a stop-loss at the lower end of the gap.
Downside Breakaway
If the gap is accompanied by heavy volume, go short and place a stop-loss at the upper end of the gap.
Continuation Gaps
Continuation gaps occur near the middle of strong trends and are useful in projecting how far the trend will continue. They are followed by new highs in an up-trend or new lows in a down-trend, which distinguishes them from exhaustion gaps. They are not normally closed.
Trading Rules
If volume is strong (up at least 50%), trade as for breakaway gaps. Enter the trade early and wait for new highs (or new lows in a down-trend) to confirm the pattern. If there are none in the next few days then exit immediately — it could be an exhaustion gap.
Exhaustion Gaps
Exhaustion gaps occur at the end of a strong trend and are the last surge before the trend expires, normally on heavy volume. They differ from continuation gaps in that they are not followed by new highs (in an up-trend) or new lows (in a down-trend) and are closed shortly afterwards.
Trading Rules
Upward Exhaustion Gap
Sell short (or close your long position) and protect yourself with a stop above the last high.
Downward Exhaustion Gap
Go long (or close your short position) with a stop below the latest low point.
Island Clusters
Look out for island clusters, identified by an exhaustion gap followed (after a few days) by a breakaway gap in the opposite direction, they are powerful reversal signals.
Trading Rules
Trade in the same way as exhaustion gaps.
文章翻譯由兄弟財經提供
本文來源：http://www.incrediblecharts.com/technical/gaps.php