information to make the contract decision. Cue bids have been part of the Acol system from the early days. Grand slam force The grand slam force uses a direct bid of 5NT to query the quality of partner's trump suit. It cannot be used following Blackwood because the bid of 5NT asks for kings, but it can be used following cue bids or Gerber. Splinter bid Splinter bids are a variety of cue bids. Splinters are used early in the bidding to communicate a strong hand, with a fit for partner's last bid suit and a side-suit singleton or void. The splinter bid is a double jump shift to the singleton or void suit. Partner of the splinter bidder will then typically bid game or proceed with cue-bids to investigate the possibility of a slam. Swiss convention In the Swiss convention, in response to an opening 1 or 1, a bid of 4 or 4 shows four-card support for partner's suit, about 13–15 points, and two or three aces respectively. Alternatively, the bids of 4 and 4 can be used to show trump quality; the specific meaning of the two bids varies between partnerships. Asking bid Given a hand which justifies slam exploration, an Asking bid pin-points a potential weakness. As in Blackwood, one partner takes control and asks the other for his holding, but as in cuebids, it is related to a specific suit. The partner replies stepwise to communicate features of the queried suit. Asking bids were devised by Alan Moorehead and developed by Ely Culbertson and are an alternative to cuebids. They are still used in some artificial systems, such as Precision Club. Serious 3NT A "Serious 3NT" is used by one partner during a cue bidding sequence to indicate a strong slam try. A cue bid that bypasses 3NT indicates a control while denying a strong hand (in case partner is strong). Last Train A bid just below game level, in an agreed suit, suggests the possibility of a slam. Relay bid Relays form a highly artificial codified scheme, where one partner takes full control early in the auction and just bids the cheapest available bids (relays), and the other describes distribution and controls in detail. The scheme based on relays, where one partner describes an absence of controls (rather than presence, as in cue bids), is known as Spiral scan, and can be combined with