Section 5: Rules of Play
5.1 Game Structure
A standard game consists of 10 ends (8 ends in Mixed Doubles, per R17(c)). Each end is analogous to an inning in baseball: both teams deliver all their stones, and then the end is scored. In the standard four-player game, each team delivers 8 stones per end (2 per player), for a total of 16 stones per end. Deliveries alternate between teams.
5.2 The Hammer (Last Stone Advantage)
The team that delivers the last stone in an end is said to have the hammer. Under Rule R5(a), unless predetermined or decided by the Last Stone Draw (LSD), teams use a coin toss to determine which team delivers the first stone of the first end; this order is maintained until one team scores, after which the team that most recently scored delivers the first stone in any subsequent end — meaning the team that did not score holds the hammer. If an end is blanked (no score), the team that had the hammer retains it. Deliberate blanking — intentionally preventing a score — is a legitimate strategy to retain hammer for the next end.
5.3 Stone Delivery
The delivery is the fundamental action in curling, governed by Rule R5:
- Starting position: The player places one foot in the hack and positions the stone on the ice ahead of the hack. Right-handed deliveries are made from the hack on the left of the centre line, and left-handed deliveries from the hack on the right; a stone delivered from the wrong hack is removed from play (R5(c)).
- Backswing and slide: The player draws the stone back, then pushes forward from the hack into a gliding lunge, sliding along the ice on the slider shoe.
- Release: The stone must be delivered using the handle, and must be clearly released from the hand before it reaches the hog line at the delivery end (R5(d)–(e)). If the stone is not released in time, it is immediately removed from play by the delivering team; if not immediately removed and it strikes another stone, the delivered stone is removed and any displaced stones restored (R5(f)).
- Rotation (turn): As the stone is released, the player imparts a slow, deliberate rotation. An in-turn rotates the stone clockwise (for a right-hander), causing it to curl to the right. An out-turn rotates counter-clockwise, causing it to curl left. Typically 2–3 full rotations over the length of the sheet.
- Weight (speed): The force applied during delivery determines how far the stone travels. Weight control is one of the most difficult skills in curling and is measured by timing the stone between hog lines (split times).
A stone is considered in play once it reaches the tee line at the delivery end (hog line for Wheelchair Curling), and is considered delivered once it reaches the hog line at the delivery end (R5(g)).
5.4 Sweeping
Sweeping is a critical skill that allows players to influence a stone's speed and trajectory after release:
- Mechanics: Sweepers vigorously brush the ice surface directly in front of the moving stone. This friction heats the pebble, creating a thin film of water that reduces friction between the stone and ice.
- Effects: Sweeping causes the stone to travel farther (by reducing friction) and straighter (by reducing curl).
- Between hog lines: A stationary stone must be set in motion before it can be swept. Once set in motion by a delivered stone, directly or indirectly, it may be swept by any one or more of the team it belongs to, anywhere in front of the tee line at the playing end (R8(b)).
- Behind the tee line: Behind the tee line at the playing end, only one player from each team may sweep at any one time — any player of the delivering team, but only the skip or vice-skip of the non-delivering team (R8(f)). The delivering team has first privilege of sweeping its own stone but must not obstruct the opponent's sweeping (R8(g)).
- No sweeping before hog line: A delivered stone must not be swept until it has crossed the hog line at the delivering end (R8(e)).
Rule R8(a) of the WCF's August 2026 Rules of Curling sets out specific restrictions on sweeping technique: sweeping may be in any direction and need not cover the entire width of a stone, but the brush head must not be raised in front of a moving stone, must not deposit debris in front of a moving stone, and a sweeping motion must finish to either side of the stone rather than in front of it. In officiated play, umpires observe sweeping under R8(a); if an umpire sees a team sweeping its own stone in violation of these restrictions, an official warning is issued to the entire team. Any subsequent violation by the same team during the same event is penalised: if it occurs during a Last Stone Draw, the maximum distance achieved is recorded against the team; if it occurs during a game, the non-offending team may choose either to let the delivered stone remain in play or to remove it and restore any stones displaced by the violation to their prior positions (R8(a)).
5.5 Free Guard Zone Rule
The Free Guard Zone (FGZ) rule is one of the most important strategic rules in modern curling. Under Rule R6(a)–(b), a stone that comes to rest between the hog line and the tee line at the playing end, excluding the house, is deemed to be within the FGZ. If, prior to the delivery of the sixth stone of an end, a delivered stone causes an opposition stone to be moved directly or indirectly from the FGZ to an out-of-play position, the delivered stone is removed from play and any displaced stones are restored by the non-offending team to their positions prior to the violation (R6(b)).
A related provision, the No-Tick Shot rule (R7), applies before the delivery of the sixth stone of an end: if a delivered stone causes an opposition stone touching the centre line within the FGZ to be moved to an off-centre-line position, or to a position outside the FGZ, the non-offending team may choose either to remove the delivered stone and restore all displaced stones to their prior positions, or to leave all stones where they came to rest (R7(a)). If the stone is instead moved from the centre line to an out-of-play position, the ordinary FGZ rule (R6(b)) applies. Neither R6 nor R7 apply to Wheelchair Curling or Mixed Doubles (R6(c), R7(c)).
5.6 Mixed Doubles Specific Rules
- Pre-placed ("positioned") stones: Before each end, one stone per team is pre-positioned at the playing end. Under Rule R17(f), as it applies from the 2026–27 season, the two placement options are Position A — a guard stone bisected by the centre line, placed immediately in front of or behind one of four marked points on the centre line at 4 ft 6 in (1.372 m), 6 ft 6 in (1.981 m), 8 ft 6 in (2.591 m), and 10 ft 6 in (3.200 m) from the outermost edge of the top of the house — and Position B — a stone in the back of the house, bisected by the centre line, with its back edge aligned to the back edge of the 4-foot ring. One team places its stone in either Position A or B, and the opponent's stone is placed in whichever position remains (R17(f)). This four-point centre-guard layout replaces the previous three-marked-point, six-option system used through the 2025–26 season.
- Power Play: Once per game, when it holds the decision on placement, a team may invoke the Power Play (not available in extra ends). The in-house stone (Position B) is moved to either side of the house, with its back edge on the tee line at the point where the 8-foot and 12-foot rings meet; the guard stone (Position A) is shifted to the same side of the sheet, at the same distance from the house used for the centre guard that game (R17(f)(III)).
- Decision on placement: Teams use the LSD to determine which side has the decision on placement in the first end (the lesser LSD distance decides); thereafter, the team that did not score in the previous end has the decision. If neither team scores, the team that delivered the first stone of that end retains the decision for the next end (R17(g)).
- Sweeping: While a team is in the process of delivery, the non-delivering player may be anywhere on the team's sheet. After delivery, either or both players may sweep their team's delivered stone and any stones it sets in motion, anywhere in front of the tee line at the playing end, including during the LSD (R17(l)).
- Protected stones: The standard FGZ rule (R6) does not apply in Mixed Doubles (R6(c)). Instead, under R17(e), if a delivered stone causes any previously delivered or placed stone to be moved to an out-of-play position before the delivery of the fourth stone of an end, the delivered stone is removed and the displaced stone restored — in effect protecting stones delivered or placed through the first three deliveries of each end.
5.7 Strategy and Shot Types
- Draw: A stone delivered to come to rest at a specific location, typically in the house.
- Guard: A stone placed in front of the house to protect a scoring stone behind it.
- Takeout: A stone delivered with enough weight to remove an opponent's stone from play.
- Hit-and-roll: A takeout where the delivered stone rolls to a strategic position after contact.
- Freeze: A draw that comes to rest directly against an opponent's stone, making it difficult to remove without also removing the frozen stone.
- Raise: A stone that strikes a stationary stone (often a guard) and promotes it into the house or to a better position.
- Peel: A takeout of a guard where the delivered stone also exits play, clearing the path.
- Come-around: A draw that curls behind a guard stone and comes to rest in a protected position.
- Angle raise: A shot that strikes a stone at an angle to redirect it to a desired target.
5.8 Timing and Clocks
At WCF international events, thinking time clocks are used to manage the pace of play. Each team's clock runs only while that team is making decisions (from the moment the opponent's stone comes to rest until the delivering player's stone is released):
- 10-end games: 38 minutes of thinking time per team.
- 8-end games (Mixed Doubles): 22 minutes of thinking time per team.
- Extra ends: Each team receives 4 minutes 30 seconds of additional thinking time per extra end.
Travel time (walking between ends, getting into position) does not count against thinking time. If a team's thinking time expires, the team forfeits the game.