Less than 30 years ago, nearly half of the golf courses in America had nine holes. There was no stigma to that number. The nine-hole golf round was as common as a slice off the first tee.

As golf boomed late in the 20th century, the vast majority of new courses had 18 holes, and gradually, as everything in golf seemed to grow bigger and longer, the 18-hole round was granted an unofficial, but understood, imprimatur as real golf.

Which left a nine-hole round as something else.

None of this was done purposefully. Yes, tournament golf was most commonly 18 holes — the number harks back to St. Andrews in Scotland, even if that number in the mid-1700s could just as easily have settled at 14 or 22.

Whatever the official number, for decades, the nine-hole round was nonetheless widely accepted. In America, most of the early golf courses were nine-holers. The first U.S. Open, in 1895, was played on a nine-hole course.

More 18-hole courses were built in the middle part of the last century, but playing only nine holes on those tracts was still commonplace well into the 1980s.

The 1990s changed everything. That was when everything about golf was aggrandized. Remember when everyone from Tiger Woods to you and me wore oversized golf shirts with sleeves that hung down to our forearms? And we took five hours — or more — to play 18 holes.

We know what happened to the ever-ballooning game of golf. Things have been substantially trimmed since then. And if the five-hour round has not disappeared, some golfers have, walking away because they do not have time for a round of 18.

To the rescue: the nine-hole round.

“We’ve got to get some people thinking again about nine holes that take two hours to play,” said Ted Bishop, the president of the PGA of America and the owner of a 45-hole public golf facility south of Indianapolis. “It’s a good way to target lapsed golfers and new golfers. The 18-hole round has its place, but let’s see how many people we can attract to the game with an offer of a quick nine holes.”

Bishop offers a $19 nine-hole round seven days a week, with or without a golf cart, after 4 p.m.

“It’s brought a real spike in the number of rounds played,” Bishop said. “And it’s been a lot of people I haven’t seen before.”

Earlier this month, the PGA of America teamed with the United States Golf Association in an initiative spearheaded by Golf Digest called Time for Nine. The magazine’s June issue, which is on newsstands, starts a campaign for nine-hole play.

Golf Digest plans to create a list of nine-hole courses that will focus on promoting nine-hole rounds for men, women, juniors and families on layouts that make it easy to do so.

The list will appear at Golfdigest.com, and golfers are encouraged to submit qualifying courses to editors@golfdigest.com, 9isfine@pga.com or Timefor9@usga.org.

“We’re not trying to get everyone who plays 18 holes to play nine holes instead,” Jerry Tarde, Golf Digest’s chairman and editor-in-chief, said.

“We’re after the people who aren’t playing because they think golf is a half-day proposition, which it isn’t.

“The message is that nine-hole golf is legitimate golf. It is not half golf or kids’ golf.”

Although about 80 percent of American golf courses have layouts that bring the ninth hole back to the clubhouse — making it easy to charge for and route golfers on nine-hole cycles — many courses do not offer stand-alone, nine-hole green fees. That is something the initiative hopes to change.

“As an industry, we must work to promote the nine-hole round as a complete and enjoyable golf experience, consistent with the traditions of playing the game,” Glen D. Nager, the president of the USGA, said.

And for people worried about their handicaps, the USGA wants golfers to know that nine-hole rounds are fully compatible with its handicap system.

There is no doubt that the push to promote nine-hole rounds reflects a reality that most of us now work longer hours and have more demands on our weekend recreational time. As Tarde said: “Every other recreation, it seems, takes more or less two hours: movies, dinner, cocktail parties, tennis, bowling, going to the gym. If golf were invented today, it would be a nine-hole game.”

There are other reasons to consider a nine-hole round when a full 18 holes may not fit your plans.

A nine-hole round, like many of the more than 4,000 old-style, nine-hole courses still remaining in America, is almost a state of mind. It has a separate pace from its full-fledged brethren, which is not to denigrate an 18-hole round and the distinctive rewards it yields.

But a nine-hole round seems inherently relaxed, an enterprise that is neither hurried nor filled with expectation. It feels more like leisure, which is the goal, isn’t it?

“Often at 5 p.m., I’ll go to the range and beat balls for two hours,” Bishop said last week. “The other day at 5, I went and played nine holes with my daughter instead. I told my wife later that I wasn’t as tired, and I might have improved my game more, too.

“A light went on in my head. I’m not going to beat so many balls at the range. I’m going to go play golf.”

I remember doing something very similar a few years ago, pulling off the highway toward the end of a long day to play nine holes with my 11-year-old son at the public Rip Van Winkle Country Club in the foothills of the Catskill Mountains in New York. The course, known as the Rip, was designed in 1919 by Donald Ross. Green fees were about $15.

I don’t remember our scores from that evening. I do remember a dog lazily chasing a deer across one fairway. I recall ducks quacking, a fish jumping in a pond and a stunning view of a mountain ridge. About two hours later, we were back in the car refreshed.

Golf is many things to many people, as it should be. But we can keep more people in our flock, and attract others to join us, if we endorse the most simple, natural and unpretentious forms of participation.

Inviting people to come out for an easy, quick nine holes is a good way to start.