Zendo shorthand for "A koan has the Buddha nature". This is typically used within the context of secret rules that frequently start with this phrase.

Example:

  • AKHTBN if and only if it contains a red piece.

The phrase "if and only if" is also frequently shortened to the logician's "iff", yielding:

  • AKHTBN iff it contains a red piece.

AKHTBN should nearly always be followed by "if"/"iff" or "unless", in a correctly-formed Zendo rule.