What is a 'family fork', a single move attacking three or more pieces at once?
These answers restate the rules implemented by our open-source engine, which follows the WXF laws and is regression-tested against the official 110-diagram repetition casebook. Where an answer refers to a specific position, that position lives on the linked reference page, where the build verifies it against the engine before publishing.
Direct answer
A family fork is one piece, most often a horse, attacking three or more targets at the same time, an escalation of the ordinary two-target fork. Where a normal fork leaves the defender choosing which single piece to save, a family fork can leave nothing left to choose, since even saving one piece does not address the others.
Why it is rarer than a normal fork
Reaching a square that simultaneously attacks three well-placed enemy pieces takes both a specific alignment of the opponent's pieces and a horse with both legs genuinely clear, which is a much less common coincidence than the two-target version covered in what a horse fork is. It usually appears in a crowded middlegame rather than a simplified endgame, where there are simply more pieces available to be caught in the same net.
What makes it so hard to defend
Against a normal fork, the defender at least gets to keep the more valuable of the two targets. Against a genuine family fork, especially if the general itself is one of the pieces attacked, there may be no reply that saves everything, turning what looks like a single tactical shot into a decisive material swing.
Related questions
Does the general count as one of the 'family'?
Yes, and a fork that includes the general is the most dangerous version, since check forces an immediate reply regardless of what else is being attacked.
Can a chariot or cannon produce a family fork too?
Less commonly, since it requires an unusually generous alignment of targets along a single line, but it is not impossible.
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