I wrote the article - It's interesting that 22 years after I wrote the article 'Side suit signals', discussion appears here. I'm working on some more complex variations of the signal now, but as it was originally postulated, it's not particularly difficult. The key factors are; 1) Dummy has a long dangerous suit with no side entry 2) It is clear to both defenders that if declarer plays this suit early, before a defender has managed to discard once or twice in the suit, then the defender with the Ace is going to have to commit himself before partner plays, THEN, so long as 3) a defender was not simply playing 3rd hand high initially, or 4) it is clearly not a case of attitude required in the led suit, THEN the player without the Ace will give a Side suit signal, using the same count method (standard or upside down, it matters not), and will signal count in the CRITICAL suit with the count card he plays in the played suit. Jeff Rubens and the American Bridge World were happy with the term Side suit signal, so why change it to offsuit signal? The example hand by Inquiry (post #9) is a great example. As it happens, it's not needed because declarer is not a lunatic, and can't have DJx. But one could change a few things, or the final contract, and then it would be critical for east to give partner the count of the diamond suit with his choice of card from the club suit.