A bullish belt hold opens at the low, often gapping down, and closes near the high. A bearish belt hold opens at the high and closes near the low. It is essentially a marubozu appearing counter to the recent direction.
The message is a complete reversal of intent within a single period: the side that controlled the open was overrun immediately and never regained ground.
It is a weak standalone signal with a high false rate, and like all patterns requiring an opening gap it is largely confined to daily equity charts. Its main use is as corroboration when it coincides with a level, a change-of-character, or a volume-climax.
Related: marubozu, kicker-pattern, gap