2B Patterns are described as failed Double Top and Double Bottom patterns. They are most powerful patterns but work well in larger time-frame charts where as in small-time frames, they are only 50% successful.
2B Patterns form when price fails to trade above previous new High or below previous new Low(see also 1-2-3 reversal pattern). 2B Patterns also have very specific rules to trade.
The 2B pattern rule applies when prices make a new high or new low. They pull back for a healthy retracement. After the retracement, the price tries to retest the ‘new’ high or low. When after the retest price breaks the previous high or low but couldn’t hold above it or below it, that signals a potential trend reversal. This setup is very powerful and signals the beginning of a correction.