A spring is a false break below support at the end of an accumulation range. Price dips beneath the obvious low, triggers stops and tempts fresh shorts, then quickly recovers back into the range — trapping sellers as demand takes over.

Why the spring works
The dip below support flushes out the last weak holders and lets the composite operator absorb their supply cheaply. The fast recovery on strong demand shows sellers could not hold their advantage — a classic effort-versus-result tell that buyers are now in charge.
The best springs recover quickly and decisively, ideally on rising volume as price climbs back inside the range. A spring that is followed by a low-volume test which holds above the spring low is especially constructive.
Entry and stop logic
A common approach is to enter as price reclaims support, or on the successful test that follows, and to place the stop below the spring low. If price falls back beneath that low and stays there, the spring has failed and the setup is invalid — a clearly defined risk point.
A spring is a shakeout below support that recovers fast — enter on the reclaim or test, with a stop below the spring low.
Not every break below support is a spring; sometimes it is simply a genuine breakdown. That is precisely why the stop matters — the setup tells you exactly where it is wrong, and sizing keeps a failed spring small.