[Kim Maengnyeong's Golf English Conversation] "What Is the Reference Point for a Glass Plate Green?"

The ball rolls farther as the green speed increases.

'Green Speed'.

It is a measure of how far the ball rolls when putting. Naturally, the faster it is, the farther the ball rolls. A higher number means the ball rolls better. The United States Golf Association (USGA) has measured about 1,500 greens using a stimpmeter since the late 1970s and established five standard speed categories for greens' ball roll distance. The first set applies to tournament play, and the latter to regular membership play.

1. Fast: 320cm (10.5ft) or more, 259cm (8.5ft) or more

2. Medium-fast: 289cm (9.5ft) or more, 228cm (7.5ft) or more

3. Medium: 259cm (8.5ft) or more, 198cm (6.5ft) or more

4. Medium-slow: 228cm (7.5ft) or more, 167cm (5.5ft) or more

5. Slow: 198cm (6.5ft) or less, 137cm (4.5ft) or less

If the green speed is between 400 and 460cm (13 to 15ft), it is truly a 'glass-like green.' The notorious US Open green speed ranges from 420 to 442cm (14 to 14.5ft). Augusta National, where the Masters is held, has a green speed of over 400cm with grass length as short as 0.3175cm. In Korea, both men's and women's professional tournaments set green speeds at 320cm (10.5ft) or higher. The green speed tends to be slower in the moist mornings and evenings (The green is usually slow in the morning).

The green becomes fastest around noon as it dries out. Depending on the season, green speed is faster from early winter to spring when grass growth is dormant, while it slows down from May through summer when the grass grows. During summer, the green is fast in the morning but slows down in the afternoon due to grass growth. Generally, elevated greens play fast (The plateau green plays quick), whereas sunken lowland greens play slow (The basin green plays slow).

Here is a conversation about green speed.

Golfer: How is putting on the greens today?

Caddy: The greens are slow (heavy) on rainy days, so you need to stroke your putt stronger than usual.

Golfer: It's nice weather, and a great day for golf.

Caddy: Yes it is, but you have to be aware that the putting green will be dry and fast.

Golfer: Is this putt downhill and fast?

Caddy: No, the green is usually slow in the morning.

Written and photographed by Kim Maengnyeong, Golf Columnist