Homo sapiens did not stand upright and then go straight to bouldering V17. The V-grades and French Fontainebleau grades that are today’s gold standards took time to disseminate, with other scales proposed along the way. In fact, it was John Gill’s B-system, advanced over a half-century ago as Gill devoted himself almost exclusively to bouldering, that set the stage for today’s popular, open-ended V-system.

1. Before Gill proposed the B-system in 1958, problems largely went ungraded—bouldering had been seen as a fun, mildly competitive diversion or “practice climbing” for roped objectives. “As far as I know, we had no bouldering grading system but used the grades we applied to climbs,” says Royal Robbins of the problems he and other California pioneers did at Stoney Point, Yosemite, and elsewhere. “If they were hard enough, we called them 5.9+. It was just training for the real, big stuff.” Gill also used route climbing’s Yosemite Decimal System until he began pulling moves harder than 5.9.

2. The B-system had three tiers: B1 was “difficult,” denoting the highest level in roped climbing (about 5.10 trad at the time); B2 was “very difficult”—or greater than 5.10—a category for stouter, “bouldering-level” problems; and B3 meant the “limit,” a problem done only once (or, as Gill wrote in his 1969 essay “The Art of Bouldering,” is “very rarely repeated, although frequently tried without success”). Repeats, even by the first-ascent party, automatically dropped the grade.

Read this: Our bio of John Gill

3. Gill’s rating scheme never caught fire like the V-scale for two reasons: firstly, because it was too fluid (a B1 put up in 1958 would naturally be easier than one done in 1968, when standards had risen), thus thwarting easy comparison; and secondly, because of Gill’s outlying talent. Says Richard Goldstone, who bouldered with Gill in the Tetons, southern Illinois, and the Needles, “Ninety-nine percent of the existing boulder problems were B1s in John’s system. He was the only person in the U.S. bouldering harder than that.” Indeed by using gymnastic training techniques and employing dynamic motion, Gill had completed, as he wrote, “short pitches or boulder problems—by 1958 and 1959—that would today be rated… V9 to V10, but were then simply ‘more difficult’ than the new 5.10s.”

4. In “The Art of Bouldering,” Gill also advanced an “E-system,” or an elimination system for the hardest problems. An E-1 would be a problem so tough only one person had climbed it, E-2 had only two ascensionists, and so on up to E-10, after which the rating would be dropped. Prescient about today’s endless V-bickering, Gill also wrote, “Reach and body compactness would make the B-system absurd for occasional problems, and climbers of different strengths would dispute the grading.” Not so with the E-system, which emphasized “the accomplishments of certain climbers and not the inherent difficulties of the rock.”

5. Today, the Font scale holds more or less the same level of global sway as the V-scale: Despite the fact that it’s been around for decades longer, it never crossed the pond, because until the last quarter century, climbers rarely bouldered internationally. Nonetheless, like the V-scale, the Font scale’s open-endedness has given it staying power: Michel Libert’s L’Abbatoir, done in 1960, is still le forêt’s first and benchmark 7A (V6), even if Font’s current hardest problem merits 8C+ or 9A (V16 or V7)… depending on who you ask. (The Font scale often uppercases the letter to distinguish it from the French route-climbing scale.)

6. Everybody knows that the V-scale takes its name from John Sherman’s nickname, “Verm” or “Vermin.” But did you know it was his publisher for the 1991 edition of the Hueco Tanks Climbing and Bouldering Guide, George Meyers of Chockstone Press, whom we should really thank? When Sherman turned in the manuscript around 1989, he deliberately left the book’s ~900 boulder problems unrated. “George wasn’t going to print it if I didn’t rate all those things,” says Sherman, so over the next season he set out to adapt and codify an informal scale in use then at Hueco: the V-scale.

7. Sherman (also the author of the famous Better Bouldering handbook) said the V-scale was mostly a half-joking “ego yardstick” that he and friends used to compare their Hueco feats to classic B2s like Gill’s Pinch Overhang at Horsetooth Reservoir, Colorado. Wanting to refine the broad B2 category, the climbers had proposed three V tiers: the original V1 was Bob Murray’s Center El Murray (today V6); the original V2 was Mike Head’s Mushroom Roof (today V8); and two benchmark V3s were Nachoman and Sex after Death (today V9 and V8 respectively). When Sherman tweaked the scale for his guidebook, he expanded it and made it open-ended, realizing the limitations of the closed B-system. (Gill, too, had originally played with an open-ended system, but discarded it because he feared it might encourage number-chasing; and as Sherman jokes, “Numbers got no soul. People need to get over that stuff.”) Sherman came up with most of the book’s V grades himself, though he handed out questionnaires to solicit consensus ratings for harder problems (roughly V5 and up) from a dozen climbers, the entire pool of qualified Hueco boulderers at the time.

Read this: Everything You Need to Know to Go Bouldering Safely

8. There has been much speculation about where the scales currently top out: Does true V17/Font 9A currently exist? There are three main contenders: Nalle Hukkataival’s Burden of Dreams, Daniel Woods’s Return of the Sleepwalker, and Simon Lorenzi’s Soudain Seul. Though the former two problems are currently unrepeated, Soudain Seul has been done three times and has been subject to some grade speculation… which is nothing new. The current prevalence of the V16 grade is a relatively new thing:  In 2011, Adam Ondra established a V16, Terranova, at Holjsten in the Czech Republic, and repeated Christian Core’s 2008 problem Gioia at Varazze, Italy, saying that both felt like V16, a grade that few climbers had yet dared to propose. In an interview, Ondra said: “If these two are to be only 8Cs, OK, but in that case, grading doesn’t make sense anymore and every single top-grade boulder problem would have to be downgraded.”

9. If V17 exists, what about V18 or V19? Wouldn’t you just run out of handholds? While it’s true that rock can become too blank, American crusher Paul Robinson thinks that stratospheric grades will be realized through specialization and length: finding lines that cater to one’s specific strengths and then working them for a long time. His problem Lucid Dreaming (V15), for instance, demands two back-to-back “limitesque” (V12/V13) moves on the micro-holds he excels at. Robinson says a V17 or V18 will require that the climber simply link more sequences like this.

10. If all these scales weren’t number soup enough, consider the primary Japanese bouldering scale, the Dankyū (also knowns as the kyū/dan) system, which is based on martial arts levels and put into play on the boulders at Ogawayama. The easiest problems, as with the easiest (student) martial arts level, start at 10-kyū and work their way down to 1-kyū, at which point you graduate black-belt mastery and the Dan side of the scale, which begins with into 1-Dan (also called shodan, or “the first step”) and is roughly equivalent V7). V16, meanwhile, roughly translates to rokudan, or 6-dan; in other words, climbing V16 makes you a sixth-degree black belt!

This article originally appeared in Climbing’s print magazine in 2012 and has been updated to reflect new levels of the sport.