Falling-knife FX longs wait for a four-hour trend turn

A decline is not yet a long

The archive procedure treats a falling knife as a potential long only after an unusual bear move, and only if a technical filter shows that price has already turned up. The sequence is rule-based-entry: a fixed order decides whether to enter, stay out, or exit from market state, rather than from discretionary judgment.

Editorial interpretation: a sharp FX decline is a delayed-entry problem. First define the knife as a size-and-speed event, then require a higher-timeframe trend turn before any long is allowed.

Define the knife, then check the four-hour turn

A falling knife is defined as a drop of at least 1,000 pips within a few days, preferably within 24 hours. That event is first identified on a daily chart. The four-hour chart is used only after that higher-timeframe event is located.

The timing filter is a 20-period exponential moving average on a four-hour chart, the ema-20-four-hour rule. Price above that average is treated as evidence that the pair is moving up. In this workflow that clearance is the breakout confirmation that the decline has given way to an upward move. The stance is trend-following: take the side of an already-established upward direction, and stay out when that direction has not yet formed.

The daily-then-four-hour scan keeps the timing check from running until the unusual decline has already been found.

Two FX episodes

In the 2008 AUD/USD case, the pair fell more than 3,810 pips from 0.9849 to 0.6008 and later recovered 3,300 pips the following year.

After the June 2016 Brexit referendum, GBP/USD declined by 1,700 pips and continued lower over subsequent trading days, illustrating that a large drop can keep extending.

Editorial interpretation: the two episodes are not a performance comparison. They show why size and speed define the knife, while the four-hour trend filter decides whether a long is even allowed.