SAN RAFAEL, Calif. - Friday is April 20, or 4/20. That鈥檚 the numerical code for marijuana鈥檚 high holiday, a homage to pot鈥檚 enduring appeal and universal slang for smoking.

How the marijuana-loving world came to mark the occasion is believed traceable to five Northern California men now in their 60s with bad backs and graying hair. They are the unofficial grandmasters by virtue of the code they created nearly 50 years ago as students at a suburban San Francisco high school in 1971.

鈥淲e thought it was a joke then,鈥 said David Reddix, a filmmaker and retired CNN cameraman. 鈥淲e still do.鈥

Reddix and his four buddies 鈥擲teve Capper, Larry Schwartz, Jeff Noel and Mark Gravich鈥 were a stoner clique who hung out at a particular wall between classes at San Rafael High School. They dubbed themselves 鈥淭he Waldos,鈥 a term coined by comedian Buddy Hackett to describe odd people.

One fall afternoon in 1971 a non-Waldo classmate came to the wall with an intriguing tale and a crudely drawn map.

The map purported to show the location of a marijuana garden in the forest of nearby Point Reyes National Seashore. The classmate said the pot patch belonged to his brother-in-law, a Coast Guard reservist stationed at Point Reyes.

The classmate explained his brother-in-law, paranoid of exposure and washing out of the reserves, was renouncing ownership of the garden. He handed Capper the map and said The Waldos were welcome to the marijuana.

The five excited friends made plans to find the weed after school and decided to meet in front of the school鈥檚 statue of Louis Pasteur at 4:20 p.m., when two of them finished football practice.

They piled into Capper鈥檚 1966 Chevy Impala, popped in a Grateful Dead 8-track tape and passed around joints as they drove the 45 minutes to the coast.

The five, now firmly middle-class fathers dressed in Polo shirts and khaki pants, laugh about tumbling out of a marijuana smoke-filled car when they arrived at their destination.

鈥淚t was straight of a Cheech and Chong movie,鈥 Schwartz said.

They didn鈥檛 find the patch that day, but vowed to keep searching. They would pass in the halls and whisper 鈥420 Louis鈥 to each other if a new attempt was planned, indicating they should meet at 4:20 p.m. at the Pasteur statue.

marijuaThe patch was never found.

鈥淲e were probably too stoned,鈥 Schwartz said.

But the 鈥420 Louis鈥 stuck as code for 鈥渓et鈥檚 get high at the statue after school.鈥 Soon after, it was shortened to simply 420 and meant 鈥渓et鈥檚 get high anywhere.鈥

There were myriad reasons for the teens to speak in code about smoking marijuana in 1971. Marijuana鈥檚 growing social tolerance was still decades away and people were receiving stiff prison sentences after being caught with even small amounts.

Another big reason: Noel鈥檚 father was a narcotics agent for the California Department of Justice.

鈥淗e had an inkling we smoked,鈥 Noel said. 鈥淏ut I don鈥檛 think he ever caught on to 420.鈥

The five Waldos never moved far away and all remain close. Gravich鈥檚 youngest daughter attends his alma mater and his oldest daughter is a recent graduate. Both say they鈥檝e long been aware of their father鈥檚 involvement in creating 420.

鈥淭he kids here think it鈥檚 pretty cool,鈥 said Julia Gravich, a sophomore.

The code remained confined to The Waldos鈥 social circle until they began hanging out backstage at Grateful Dead concerts. Reddix鈥檚 older brother was friends with band member Phil Lesh and that led to backstage passes and smoking sessions with the roadies and other crew members, who picked up the code.

The number really took off in the late 1980s when flyers were circulated at Dead concerts proclaiming 420 to be the password of stoner culture. The flyers went on to explain that 420 was California police code for marijuana smoking in progress. It鈥檚 not, but that and other origin stories continue to circulate to the point that Capper and Reddix have committed themselves to preserving as much proof as they can that they are the originators.

They tracked down the Coast Guard reservist to record his recollections confirming he grew a marijuana garden and drew the map that launched the treasure hunt. With his permission, they obtained his Coast Guard records, which show him stationed at Point Reyes at the appropriate time.

They keep those records in a rented safe deposit box in a San Francisco bank where they also store other documentation, including postmarked letters they exchanged in the mid-1970s discussing 420. The San Francisco bank鈥檚 address, as it happens, is 420 Montgomery Street.

The Oxford English Dictionary added 420 to its lexicon last year after reviewing the Waldos鈥 records and credits the men as the creators.

Millions of dollars have been made over the years exploiting the number, from T-shirts and hats to cannabis businesses with 420 in their names. Hotels and tour companies advertise themselves as 鈥420 friendly鈥 and dating sites contain listings for people 鈥420 compatible.鈥

Though dozens of 420-related trademarks have been issued to various companies, The Waldos hold only one.

But they are starting to cash in, if only a little.

Lagunitas Brewing Co. in nearby Petaluma is set to release its seasonal 鈥淭he Waldos Special Ale鈥 on April 20. The brewery has given the five lifetime passes for free beer.

The Waldos also struck their first business deal with a cannabis business. They are endorsing an Oakland company鈥檚 vaping pen, which of course will be released on Friday at 4:20 p.m. All five plan to be at the company鈥檚 release party and plan to donate proceeds to the Drug Policy Alliance, a nonprofit group that lobbies for marijuana legalization.

鈥淓veryone has cashed in on 420,鈥 Noel said. 鈥淲hy not us?鈥