Harami

A small body contained entirely inside the previous bar’s larger, opposite-coloured body: the trend paused. Japanese for ‘pregnant’ — the large bar carries the small one.

Signature

Harami(lookback, on=<source>)

Argument	Type	Required	Notes
lookback	int Param	Yes	Pinned at 1. Bounds 1–1.
on=	symbol	No	Source symbol. Defaults to the trade symbol. Reads open and close.

Formula

This body sits inside the previous body and is smaller; +1 when the prior bar was black, −1 when it was white.

Warmup

One bar of state.

Reading the value

p.value
p > 0

Pattern indicators return a flag, not a level: +1 bullish, -1 bearish, 0 absent. They are zero on most bars by design, so treat them as event triggers rather than as something to smooth or cross.

Example

class HaramiPause(Strategy):
    """Act on the pattern only in the direction of the longer trend."""
    trade = Symbol()
    sizing = FixedCapital()

    def execute(self):
        p = Harami(1, on=self.trade)
        sma = SMA(50, on=self.trade)
        if p.value > 0 and self.trade.is_flat:
            self.buy(self.trade, reason="Bullish harami")
        if self.trade.is_long and self.trade.close < sma.value:
            self.sell(self.trade, self.trade.position, reason="Trend lost")

Notes

• A pause signal, not a reversal: it says the trend stopped, not that it turned. ThreeInside adds the confirming bar that makes it a reversal.