MLR G-11 enables a committee to limit players to using only the yardage book that it has approved for use in the competition.
This local rule is intended only for the highest levels of competitive golf and, even then, only for competitions where it is realistic for the committee to undertake an approval process for yardage books. It will be available starting 1 January, 2022.
The local rule gives a committee the ability to establish an officially approved yardage book for a competition so that the diagrams of putting greens show only minimal detail (such as significant slopes, tiers or false edges that indicate sections of greens).
In addition, the local rule limits the handwritten notes that players and caddies are allowed to add to the approved yardage book.
The purpose behind the local rule is to ensure that players and caddies use only their eye and feel to help them read the line of play on the putting green.
The R&A and the USGA developed MLR G-11 in response to feedback from several professional tours.
Speaking earlier this year, four-time major winner Rory McIlroy said: “I use a green book, and I'd like to get rid of them. Most guys on tour are in the same boat, that if it's going to be available to us and it helps us, people are going to use it.
“But I think for the greater good of the game, I'd like to see them be outlawed and for them not to be used anymore.
“I think reading greens is a real skill that some people are better at than others, and it nullifies that advantage that people have. Honestly, I think it's made everyone lazier. People don't put in the time to prepare the way they used to."
As the local rule should only be adopted at the highest levels of competitive golf, all other golfers will continue to be able to use green-reading tools so long as they meet the requirements established in 2019.