A complicated slam convention showing aces and kings as well as asking for them. The 4NT bid shows three aces or two aces and a king of a suit bid by the partnership. The responses are: with two aces or one ace and the kings of all suits bid by the partnership, bid 5NT.
If holding no ace, bid five of the lowest suit that the partnership has bid. Holding one ace, bid the suit with the ace at the five- level, or at the six-level if it is the ace of the lowest suit genuinely bid by the partnership.