Declarer changes designation of card to be played from Dummy
During the play of a No Trump contract, Dummy has a solid 6 card Diamond suit in Dummy and calls for Dummy to 'Run the Diamonds'. After Dummy has led the first 4 Diamonds, Declarer now calls for the lead of a Club. Does 'Run the Diamonds' commit Dummy to run all of the Diamonds? Whatever the decision, what is the relevant Rule?
Comments
Page 127 of the White Book gives this answer
Law 46 Incomplete or Erroneous Call of Card from Dummy
8.46.1 Law 46: “Run the clubs” [WBFLC]
Declarers sometimes give an instruction to Dummy to run a suit and then leave him to do this without giving, as is procedurally correct, a separate instruction for each card. A question can arise as to when the second, or a later, card is played from dummy, since the Declarer is not able to stop play of the card once it is played. The Committee ruled that the card is deemed to be played when Declarer’s RHO follows to the trick.
However, the committee deprecates instructions given to Dummy in this irregular manner.
[WBFLC minutes 2000-01-12#6]
Suppose declarer instructs dummy to “run the clubs”. Declarer may change this instruction at a later trick, and a card from dummy may be changed until declarer’s RHO plays to the trick. At this point the card becomes played.
The relevant rule, as you ask, is that “Run the clubs” is not part of Bridge, so there is no relevant law, as with other extraneous remarks, apart from L73D. If an opponent is damaged through the expectation that all the clubs will be played an adjustment under L73E2 is suitable.