Three white soldiers is a bullish continuation-or-reversal pattern made of three consecutive long bullish candles, each opening within the previous candle’s body and closing at or near its high with small upper wicks. The steady, overlapping advance is read as sustained buying pressure rather than a single volatile spike.
Its bearish counterpart is three black crows: three long down candles in the same overlapping fashion. Both patterns are valued because they show momentum building over several periods, which is harder to fake than one large candle. Appearing after a base or a pullback, three white soldiers is taken as confirmation that buyers have taken durable control.
The caution is that by the time three strong candles have printed, much of the move may already be done — entering on the close of the third candle often means buying after an extended run, with a far stop. As with every pattern, the qualifying rules (minimum body size, maximum wick, required overlap) must be fixed before any backtest can mean anything.