In a joint release Tuesday, the R&A and USGA announced their plans to limit the use of green-reading materials beginning in 2019, “reaffirming the need for a player to read greens based on their own judgement, skill and ability.”

Starting Tuesday, the proposal detailed below will be subject to a six-week period of “feedback and consultation with interested parties.”

The final regulations will then be published in an interpretation of Rule 4.3 – the use of equipment – and adopted with the rest of the new Rules of Golf on Jan. 1.

The release did stress that both yardage books and handwritten notes will still be allowed, with the caveat that those handwritten notes “cannot be used to create either a direct copy or a facsimile (replica) of a detailed green map.”

“We have looked carefully at the use of these green-reading materials and the extremely detailed information they provide and our view is that they tip the balance too far away from the essential skill and judgement required to read subtle slopes on the greens,” The R&A’s Executive Director of Governance David Rickman said a statement. “It is important to be clear, however, that we still regard the use of yardage books and handwritten notes to be an entirely appropriate part of the game.”

“Both the USGA and The R&A are committed to the position that a player’s ability to read their line of play on the putting green is an essential skill that should be retained,” added Thomas Pagel, senior director of the Rules of Golf and Amateur Status for the USGA. “The focus of the interpretation is to develop an approach that is both effective and enforceable.”

The governing bodies’ four-point propsosal is listed here:

Minimum Slope Indication Limit – A minimum slope indication limit of 4% (2.29 degrees) is proposed (this includes lines, arrows, numbers or any other indicators); this will have the effect of eliminating such indicators of slope from those areas of the putting green where the hole is most likely to be positioned (which tend to be cut on reasonably flat sections of the putting green with a degree of slope of less than 3.5% – or 2 degrees). This proposed limit also equates roughly with the amount of slope that is readily visible to the naked eye.
Maximum Scale Limit – A maximum scale of 3/8 inch to 5 yards (1:480) is proposed; this will limit the size in print form to a pocket-sized publication and has the effect of restricting the space for handwritten notes (also referenced below).
Indicative Information – General information that is included in traditional yardage books or course guides, such as basic illustrations that show the outline of the putting green and include indicative information like the tops of ridges or general slopes, will continue to be permitted.
Handwritten Notes – Handwritten notes will continue to be allowed but such notes cannot be used to create either a direct copy or a facsimile (replica) of a detailed green map.