On Saturday at the Hero World Challenge, Collin Morikawa was assessed a two-stroke penalty on the fourth hole for a breach of Model Local Rule G-11, which restricts the use of green-reading materials.
According to reports on the ground, Morikawa's caddie used a device (a level) on the practice green to calculate slope which is not illegal, but he then added that info to his handwritten notes in the yardage book which is a breach of the rules.
Statement on Collin Morikawa pic.twitter.com/A2lOtxBpI3December 3, 2023
According to the USGA and under 'Model Local Rule G-11: Restricting Use of Green-Reading Materials'- Rule 4.3, and specifically Interpretation 4.3a/1, puts limitations on the size and scale of detailed green-reading materials. But 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 Committee may further restrict the use of green-reading materials by requiring that players are limited throughout their round to using only the yardage book that has been approved for use in the competition.
"This Local Rule is intended only for the highest levels of competitive golf and, even then, only to competitions where it is realistic for the Committee to undertake an approval process for yardage books. When introducing this Local Rule, the Committee is responsible for approving the yardage book that players may use, and the approved yardage book should contain diagrams of putting greens with minimal detail only (such as significant slopes, tiers or false edges that indicate sections of greens). Players and caddies may add handwritten notes to the approved yardage book to help them read the line of play on a putting green, so long as those notes are allowed under this Local Rule."
For even further clarity, the ruling goes on to say: "Rule 4.3a is modified in this way. During a round, the player may use only the yardage book(s) approved by the Committee. This restriction also applies to any other maps of the course, including hole-location sheets. Additional restrictions apply to handwritten notes and any other materials used by the player that could help read the line of play on the putting green: Handwritten notes may be added to an approved yardage book or approved hole location sheet before or during the round by the player or the player’s caddie only and are limited to information gathered by the player or caddie only.
"Handwritten notes may contain information gained only through personal experiences of the player or the player’s caddie from the course or by watching a televised broadcast, but are limited to information gained: (e.g.) while observing a ball that was rolled or played (whether by the player, caddie or someone else) or through the player’s or caddie’s feel or general observations of the putting green."
Speaking at the event, the PGA Tour’s Chief Referee, Stephen Cox, stated: “Unfortunately, the caddie used a device, a level, on the practice putting green. That’s not a breach of the rule in itself but what he did was he developed that chart or formula as a handwritten note in his yardage book. That’s where the breach occurred. Because he used it while assessing the putt [at No. 4] during his third round he was assessed a two-shot penalty.”
According to Golf Channel, Cox was reportedly informed of the possible breach late Saturday evening by playing partner, Matt Fitzpatrick, with Cox adding: "(Morikawa) was very frustrated, it’s a very complicated rule. Obviously, when we implemented it back in 2022 there was a huge amount of (green-reading) information." Morikawa was made aware of the penalty around 15 minutes before his final-round tee time.
Because of the breach, Morikawa's bogey five was upgraded to a triple bogey seven, leaving the two-time Major winner well out of contention in the Bahamas. Despite the set back, he did go on to birdie the seventh, eighth and ninth for a two-under front nine, but a double bogey six meant his inconsistent Saturday finished with a two-under round of 70.
It isn't the first time that Morikawa has been caught up in a rules incident in 2023. At the Masters, a video of the American marking and replacing his ball on the 6th hole sent social media wild, with the 26-year-old forced to clarify that: "The ball moved, and then I moved it back. Pretty standard now. Pretty routine in our rules book thankfully". Along with the explanation, Morikawa released a tweet shortly after his three-under-par round of 69.
