When a boxer is knocked down, the referee begins his normal ten count. Even if the boxer gets up before eight, the referee is required to continue the count to eight. This gives the downed boxer an extra few seconds to regain their composure before continuing the bout. It was introduced to protect the boxer from unnecessary damage.
The referee can still decide to stop the fight after the eight count if he decides to make a judgement call based on the state of the boxer.
This rule was first used in 1961 and is part of the Unified Rules of Boxing.
It is different from the standing eight count, which is where the referee can start a count at their discretion without a boxer being knocked down, if they are taking a heavy beating. This rule is no longer in use.
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