What is shot clock and possession in Water Polo?

Section 5: Rules of Play

4 periods of 8 minutes actual playing time (clock stops on every whistle)
2-minute interval between the first and second periods and between the third and fourth periods
5-minute interval at halftime (between the second and third periods); teams switch ends
Overtime (if tied): two 3-minute periods of actual play with a 3-minute interval; if still tied, penalty shootout
Penalty shootout: 5 alternating penalty throws per team; sudden-death if still level

Field players may touch the ball with only one hand at a time (except the goalkeeper)
Goalkeeper may use two hands on the ball within the 5 m area of their own goal
The ball may not be pushed underwater by any player — this is an ordinary foul
A player may not hold the ball underwater when tackled — turnover foul
Players may dribble the ball (push it ahead while swimming), pass to teammates, or shoot at goal
A player may not take the ball under the water surface to avoid an opponent

30-second shot clock: The attacking team must attempt a shot that contacts the goal frame (posts, crossbar, or goalkeeper) or enters the goal within 30 seconds of gaining possession
Shot clock resets to 30 seconds on: change of possession, a shot hitting the goal/goalkeeper, awarded exclusion foul, corner throw awarded to attacking team
Shot clock resets to 20 seconds when: an exclusion foul is awarded and the attacking team retains possession with advantage
If the shot clock expires without a valid shot: turnover — free throw to the defending team

Each team may call 2 timeouts per game (plus 1 additional in overtime)
Timeouts are 1 minute in duration
A timeout may only be called by the team in possession during a dead-ball situation
Teams huddle at their bench; the coach may provide tactical instruction

Within their own 5 m area: may use two hands, punch the ball with a fist, stand or walk on the bottom (if shallow enough)
Beyond the 5 m area: treated as a field player (one hand only, no two-hand privileges)
May not cross the half-distance line
May score goals from any legal position within their own half
May not hold the ball for more than the shot clock limit

Free throw: Awarded for ordinary fouls; taken immediately from the spot of the foul without waiting for the referee’s whistle
Goal throw: Awarded when the attacking team last touches the ball before it goes over the goal line outside the goal; taken by the goalkeeper from within the 2 m area
Corner throw: Awarded when the defending team (including the goalkeeper) last touches the ball before it goes over the goal line; taken from the 2 m mark on the side nearest where the ball crossed
Neutral throw: Referee tosses the ball into the water between two opposing players (similar to a jump ball); used for simultaneous fouls or disputed possession

4 periods of 8 minutes actual playing time (clock stops on every whistle)
2-minute interval between the first and second periods and between the third and fourth periods
5-minute interval at halftime (between the second and third periods); teams switch ends
Overtime (if tied): two 3-minute periods of actual play with a 3-minute interval; if still tied, penalty shootout
Penalty shootout: 5 alternating penalty throws per team; sudden-death if still level

Field players may touch the ball with only one hand at a time (except the goalkeeper)
Goalkeeper may use two hands on the ball within the 5 m area of their own goal
The ball may not be pushed underwater by any player — this is an ordinary foul
A player may not hold the ball underwater when tackled — turnover foul
Players may dribble the ball (push it ahead while swimming), pass to teammates, or shoot at goal
A player may not take the ball under the water surface to avoid an opponent

30-second shot clock: The attacking team must attempt a shot that contacts the goal frame (posts, crossbar, or goalkeeper) or enters the goal within 30 seconds of gaining possession
Shot clock resets to 30 seconds on: change of possession, a shot hitting the goal/goalkeeper, awarded exclusion foul, corner throw awarded to attacking team
Shot clock resets to 20 seconds when: an exclusion foul is awarded and the attacking team retains possession with advantage
If the shot clock expires without a valid shot: turnover — free throw to the defending team

Each team may call 2 timeouts per game (plus 1 additional in overtime)
Timeouts are 1 minute in duration
A timeout may only be called by the team in possession during a dead-ball situation
Teams huddle at their bench; the coach may provide tactical instruction

Within their own 5 m area: may use two hands, punch the ball with a fist, stand or walk on the bottom (if shallow enough)
Beyond the 5 m area: treated as a field player (one hand only, no two-hand privileges)
May not cross the half-distance line
May score goals from any legal position within their own half
May not hold the ball for more than the shot clock limit

Free throw: Awarded for ordinary fouls; taken immediately from the spot of the foul without waiting for the referee’s whistle
Goal throw: Awarded when the attacking team last touches the ball before it goes over the goal line outside the goal; taken by the goalkeeper from within the 2 m area
Corner throw: Awarded when the defending team (including the goalkeeper) last touches the ball before it goes over the goal line; taken from the 2 m mark on the side nearest where the ball crossed
Neutral throw: Referee tosses the ball into the water between two opposing players (similar to a jump ball); used for simultaneous fouls or disputed possession