The R&A has announced revisions to golf's equipment Rules, which are designed to enhance the benefits of accuracy by making playing from the rough a more challenging prospect in future.

The new Rules, which relate to club face grooves, are the culmination of an extensive collaborative research project between The R&A and the United States Golf Association. This research shows that modern groove configurations can allow players to generate almost as much spin from the rough as is available from the fairway, resulting in a reduction in the value of accuracy.

"Our research has involved input from both Governing Bodies, including substantial laboratory work and player testing at all levels around the world," said Dr Stephen Otto, The R&A's Director of Research and Testing.

"Contributions from golf club manufacturers in particular have been considerable and they have welcomed the opportunity to be involved in the process."

The revised Rules will significantly increase the spin differential between shots from the fairway and shots from the rough.

The new Rules will augment the existing limitations on grooves and will affect all clubs (with the exception of drivers and putters), with the new regulations limiting groove volume and groove edge sharpness. Essentially, larger volume grooves have the ability to channel away more material, such as water or grass, similar to the tread on car tyres. At the same time, sharper groove edges facilitate a better contact between club and ball, even in the presence of debris.

Both new regulations will apply to golf clubs with lofts greater than or equal to 25 degrees (generally a standard 5-iron and above) with only the rule limiting groove volume applying to clubs of lesser loft.

The Rules will apply to all clubs manufactured after 1 January 2010. Clubs manufactured prior to this date, which meet the current regulations, will continue to be regarded as conforming under the Rules of Golf until at least 2024.

It is intended that the new Rules will be introduced as a Condition of Competition at top professional level from 1 January 2010 and at top amateur level and in other professional events from 1 January 2014. The R&A and the USGA will introduce such a Condition of Competition at their respective championships in accordance with this schedule. The world's top professional tours for both men and women, and the organisers of golf's major championships, have all indicated their support for the new groove regulations and their intention to implement the Condition of Competition in 2010.

"We believe that this rule change is necessary to reinforce the importance of accuracy at the highest levels of the game. However, beyond that the new Rules will be phased in very gradually," said David Rickman, The R&A's Director of Rules and Equipment Standards.

"The vast majority of the golfing public will enjoy many years' use of their existing equipment within the Rules and this, of course, will also apply to any purchases they make from manufacturers' existing model ranges."

The new Rules on club face markings, to come into effect on 1 January 2010, will include the following two additional specifications for clubs other than driving clubs and putters: the total cross-sectional area of a groove divided by the groove pitch (width plus separation) is limited to 0.003 square inches per inch (0.0762 mm²/mm); and groove edge sharpness is limited to an effective minimum radius of 0.010 inches (0.254 mm). This limit only applies to clubs with lofts of 25 degrees and above.

The new Rules will be phased in gradually. With effect from 1 January 2010, it is intended that only the major men’s and women’s professional tours will adopt a Condition of Competition requiring the use of clubs that conform to the new Rules. The use of this Condition will be very restricted in the initial phase.

With effect from 1 January 2014, the Condition of Competition will be made available to more competition organisers and include all competitions involving ‘expert players’ (that is lower level professional events and elite amateur events). It would only be at this time, that the Condition would start to have an impact beyond the major professional tours.

All clubs (with the exception of drivers and putters) manufactured after 1 January 2010 will be subject to the new specifications on club face markings. Clubs manufactured before 2010, which conform to the current Rules but not the new Rules, can continue to be used throughout the game, except where a Committee has introduced a Condition of Competition to the contrary (see above).

The final decision as to whether golfers playing in non-elite competitions will ever have to stop using these older clubs will be taken in the future, but certain minimum time scales are guaranteed: firstly, the situation will not be reviewed before 2020; and secondly, any change of Rule would have a minimum four year lead-in period. Of course, some existing clubs will conform to the new regulations and may continue to be used indefinitely. The above provisions confirm that other ‘old clubs’ (that is pre-2010 models that do not conform to the new Rules) may continue to be used by the vast majority of golfers until at least 2024, if not longer.

For the avoidance of doubt, in recognition of the fact that many existing clubs will not conform to the new specifications, Committees of other competitions (that is all those not covered by the Condition of Competition on grooves) are authorised and will be encouraged to waive these new specifications for applicable clubs manufactured prior to 1 January 2010.