Perhaps it's time to put the Eastern/Western question to bed by introducing a third stone, a nice little clear or grey one to indicate nullity. When the BN is not clearly TRUE or FALSE about a koan, the master could put out a null stone. Using a previous example rule: "AKHTBN XIF if all it's blue pyramids are upright." When a koan has blue pyramids the truth or falsity is simple to determine, on the words "all" and "upright". When a koan doesn't have blue pyramids, truth and falsity become a matter for the philosophers to wrangle over. I suggest that for a koan without blue pyramids, the koan neither "has" nor "does not have" the BN. I might say: "The BN and this koan have no relationship to one another." or "The BN rule's predicate is not met by this koan, therefore the BN's rule cannot be evaluated against this koan" Consider: AKHTBN XIF it stops sleeping with my wife. Hellow? Database science says "null" is a distinct third state, or lack of state, whichever you like. My experience says that calling null true, or calling null false, will eventually bite you on the fanny. David L. Willson Trainer, Engineer, Enthusiast MCT, MCSE, Linux+ tel://720.333.LANS Freeing people from the tyranny (or whatevery) of Microsoft, one at a time.