This convention is again artificial bidding and meant to help a partnership decide if it has sufficient numbers of Aces and Kings to go on to a slam bid.
I mentioned that Gerber was better than Blackwood in keeping the bidding lower. This convention keeps the bidding lower still.
The asking bids for Aces are just as you have already learned. But when it comes to finding out Kings, the asking bid is not 5 Clubs in the case of Gerber, or 5 No Trump, as in the case of Blackwood. When you are doing LADDER bidding, you use the next available bid as your asking bid, and as each of the responses goes up, the bidding goes up by one degree.
So for instance if you had an asking bid of 4 Clubs, and your partner had 0 Aces, they would bid 4 Diamonds and then you would ask for Kings by saying 5 Clubs. But in ladder bidding, you would ask for Kings by saying the next available bid, which is 4 Hearts, and the responses would be 0-4 would be 4 Spades, and so on.
There is no chart to follow for ladder bidding because on each occasion, the next bid is dependant on the one before. With this bidding, you often has enough bidding space to ask for Queens as well.
63. With the hand below, assume Gerber was used for asking for Aces, what would be the asking bid and the response bid using Ladder Bidding?
a. 5 Clubs, 5
b. 4 Spades, 4 No Trump
c. 4 No Trump, 5 Clubs