'If Information Is Contained in the Yadiji Book'

Morikawa Makes Mistake at Hero World Challenge
Uses Level to Obtain Green Information from Yardage Book
Intended to Visually Assess Green Slope, Breaks, and Speed
One Rule Violation Results in 2 Penalty Strokes, Second Violation Leads to Disqualification

Even monkeys fall from trees.

This is the story of Collin Morikawa (USA), ranked 14th in the world. On the 2nd, during the third round of the PGA Tour's "special event" Hero World Challenge held at Albany Golf Course in New Providence, Bahamas, he was found to have violated a rule. Here's what happened. Steven Cox, a PGA Tour rules official, received a report that Morikawa had broken a rule during the third round of the tournament. An investigation was conducted with Morikawa and his caddie just before the start of the final fourth round, and it was confirmed to be true, resulting in a two-stroke penalty.

Collin Morikawa was penalized in the third round of the Hero World Challenge for using a yardage book containing green information identified through equipment.

Morikawa violated the rule introduced last year that prohibits the use of measuring devices to assess the green. This rule allows players or caddies to write and use information obtained through experience and observation in the yardage book containing course information. However, information obtained through devices cannot be recorded at all. The yardage book carried by Morikawa's caddie contained green information measured using a level during practice.

Referee Cox explained, "It is allowed to use a level to assess the slope of the green during practice, but writing down that information in the yardage book and referring to it during play is a violation of the rules," adding, "This is a rule that players and caddies can unknowingly break." Morikawa said, "We made a mistake, and it’s all my fault," and added, "Fortunately, it was only a single violation." He finished the tournament in 7th place after shooting four under par on the final day.

The Royal & Ancient Golf Club (R&A) and the United States Golf Association (USGA) are focusing on shortening golf playing times. This is an effort to maintain golf’s popularity. They have simplified the rules and emphasized speeding up play. These include a shot clock of 40 seconds, a maximum of 3 minutes to search for lost balls, allowing putting with the flagstick in the hole, and permitting players to use distance measuring devices. However, recording green slopes and other details in yardage books is prohibited. The intention is for players to assess green slopes, breaks, and speed solely by sight and feel.

In 2022, the R&A and USGA strengthened the prohibition related to yardage books. Only approved yardage books can be used. Information obtained by unapproved methods cannot be included. Materials that help read the line of play on the green are not allowed. This rule bans the use of advanced electronic devices. The penalty for a first violation is two strokes, and a second violation results in disqualification.

Morikawa, who violated the yardage book rule this time, is a top-tier golfer representing the PGA Tour. He was ranked number one in the world amateur rankings in 2018 and turned professional in 2019, immediately winning his first title at the Barracuda Championship in July. By June 2020, he had an impressive streak of making the cut in 22 consecutive tournaments, including the RBC Heritage. He has won two major championships: the 2020 PGA Championship and the 2019 Open Championship, and in October last year, he secured his sixth PGA Tour victory at the Zozo Championship.