Guidance to Referees and Players on Short-Range Clearances
Definitions and Abbreviations
All references to the GC Rules are to the 6th Edition.
Diagram 1 below defines the abbreviations used in this guidance:
- Aiming Angle to the line of ball centres (AA), measured in degrees.
- Initial Separation (IS) of the balls, measured in millimetres.
- Departure Angle (DA) - the angle, measured in degrees, at which the balls separate after impact.
- Striker's Ball (SB) - the ball to be struck by the mallet - black ball in the diagram.
- Object Ball (OB) - the ball being moved by SB - red ball in diagram.
Diagram 1 - Abbreviations used in Short-Range Clearance Guidance
Paragraph 4.1 of Appendix 5 of the GC Rules sets out the guidance on a stroke that involves hitting a ball towards another ball along, or close to, their line of centres (i.e. a straight, firm clearance). This is soundly based on the super slow-motion videos made by Croquet England in 2006.
Paragraph 4.2 of Appendix 5 addresses balls played at an angle to their line of centres (i.e. angled, firm clearances).
This supplementary, web-based guidance for the assistance of both referees and players, includes Short-Range Clearances involving strokes when at least one of the balls does not move very far (more than 600 mm).
The guidance includes two tables, Tables A and B, to provide easy-to-use ready reckoners for adjudicating all Short-Range Clearances.
This guidance also includes when to use the two tables; how to referee a Short-Range Clearance stroke, and the factors applicable when exercising judgement.
Straight, Firm Clearances
If a firm stroke is straight, or nearly straight (i.e., if the Aiming Angle is < 10 degrees), use the Table A Row 1 below when adjudicating whether a stroke was clean. This table incorporates the guidance in Appendix 5, paragraph 4.1.
Table A - Short-Range Clearance Decision Table A - Row 1 Highlighted.
Angled, Firm Clearances
When a ball is firmly struck at an angle to a nearby ball, the situation is more complicated.
Video evidence has confirmed that a Double Tap or Ball Crush will generally reduce the Departure Angle of the two balls after contact. In a firmly played angled clean stroke, the Departure Angle is something between 60 and 90 degrees; it is this fact which can be used to decide the fairness of such strokes.
A summary of the guidance in Appendix 5 paragraph 4.2.2 is provided in the highlighted Row 2 of Table A below.
Table A - Short-Range Clearance Decision Table A - Row 2 Highlighted.
5. Clearances Involving Gentle, or Very Angled Strokes with Small Initial Separations
For gentle clearances, or very angled strokes with small (i.e. up to 2 mm) Initial Separations, unless both balls move an appreciable distance, it is difficult to tell anything useful from the Departure Angle.
Instead, before the stroke is played, ask the player to indicate their intended line of aim and estimate how far the relevant point on the SB's perimeter will travel before it contacts the OB (i.e. the effective separation distance). If the effective separation distance is less than 4 mm, the stroke should be faulted under Rule 11.2.6.
The smaller the Initial Separation, the larger the Aiming Angle required to avoid a fault under Rule 11.2.6.
Chart 1 below, developed using trigonometry, shows the minimum Aiming Angle (with rounded values for easier usage) required to achieve a clean stroke (i.e. to achieve an effective separation distance of at least 4 mm) at different Initial Separations:
Chart 1 - Minimum Aiming Angle for a range of Initial Separations to Achieve a Clean Stroke.
Building on Chart 1, to simplify the decision making, Table B below presents the relevant guidance in tabular form:
Table B - Short-Range Clearance Decision Table B.
6. How to Referee Such Strokes
- Ask the player what they intend to do. The referee needs to know:
- what is their intended line of aim and hence what AA they intend;
- the type of stroke that they intend to play (i.e. stop (stun) shot or drive); and
- how hard they intend to play the stroke.
- Mark the balls' positions. It may also be useful to mark the intended AA using a marker placed behind the player.
- Check the separation between the balls along the line of centres. If the separation is <4 mm, also check how far the relevant point on the SB's perimeter will travel parallel to the intended line of aim before it contacts the OB.
- Ask the player to play the stroke.
- Watch the stroke - was it along the intended AA; was it a well-executed shot?
- Apply the guidance given (using the appropriate Table A or Table B) to decide whether or not to declare a fault under Rule 11.2.4 or 11.2.6.
7. When to Use Tables A and B
Chart 2 below identifies which of the two Tables to use, based on strength of stroke, Aiming Angle and Initial Separation:
Chart 2 - When to use Tables A and B.
To explain, Table A relies on measuring what happens to the balls after they have been struck. By contrast, Table B does not use this factor, because, when played gently, at least one of the balls should not move very far, making measurement of Departure Angle unreliable. Conversely, if balls start very close to one another (i.e. up to 2 mm) and are played firmly causing both balls to move significantly, that is a clear indication that the balls have not been played at a sufficient angle to avoid a fault.
Therefore, Table B uses the specific angle the mallet is played at (measured from the balls' centre line) as the key determinant, allowing for the fact that in the marginal situations identified in the Table referees will be more reliant on their judgement.
8. Exercising Judgement
Note always that poorly played strokes with excessive or lazy follow-through will be likely to cause a fault even in circumstances when a well-executed stop (stun) shot would not - this must be considered when refereeing a stroke.
Table B above identifies with yellow coloured cells some marginal circumstances when a referee will need to rely more on their experience in making a judgement based on whether a fault was more likely than not (in accordance with Rule 11.3.1).
Mindful of the minimum angle require to achieve a 4 mm effective separation distance, as defined above, referees will also need to use all of:
- The Initial Separation.
- The Aiming Angle.
- The way the balls moved, including the Departure Angle (see below).
- The sound (N.B. not a very reliable guide).
- What happened with the mallet's follow through.
- Any interaction with a hoop / peg.
When played correctly at extreme angles, the Object Ball will not move very far at all - if it moves a significant distance, then there is likely to have been a fault under Rule 11.2.6.