Decades ago, starting in the 1930s, fishermen placed obelisks along O'ahu's coastal cliffs to give an unmistakable warning: On this spot, the sea had swept across the black lava ledge and taken a life.

The shafts, which at one point numbered 50, disappeared over time, but not the danger.

Four people have died this year in waters off East Honolulu, including a tourist posing for a photograph when a huge wave swept her off Lana'i Lookout.

The city hopes to prevent such accidents and tomorrow will unveil a distinctive replica of the obelisks at China Wall. The treacherous surf spot off Portlock Point is a regular host to tragedy, claiming two lives this year — a 45-year-old fisherman in April and a 17-year-old visitor in July.

Although the first obelisk is on city land, organizers want to place several other obelisks on state land where deaths have occurred, including Lana'i Lookout, the Halona Blow Hole and Spitting Caves.

Spitting Caves, a dangerous spot where people have died jumping off the cliff, claimed the life of a 29-year-old tourist in July. He survived the jump, but panicked in the ocean and drowned.

China Wall, which is just north of Spitting Caves, is as deceptive as it is deadly. The ledges there jut forward like the steps of a staircase, ending with a 5-foot drop to the ocean.

Swimmers have found it inviting — until the passing waves slam them against the rocks.

"Although it is incredibly beautiful and looks docile, it is a very dangerous and unforgiving spot," said Dr. Libby Char, director of the city Department of Emergency Services.

Existing warnings at dangerous coastal spots did not seem to be working so Char, an emergency room physician who took her job in February, formed a task force this summer to find a better way to warn people.

They found their solution in the pages of history when John Clark, deputy chief of the Hono-lulu Fire Department, suggested the obelisks. The 59-year-old author and veteran waterman remembered seeing them as a child when his family took circle-island drives.

"And everyone, everyone — everyone — knew what they were," said Clark. "They knew someone had drowned there. Even though the messages were faded and worn away, everyone knew what the posts were."

By pure coincidence, Clark also had been writing a book on the fishermen who first put up the 6-foot-10 obelisks.

Ulua fishermen with the Hono-lulu Japanese Casting Club had drowned off the coastline between Sandy Beach and Portlock Point and they decided to put up warnings in November 1931.

A month later, one of their members was swept to his death while erecting an obelisk at a popular fishing spot near the Halona Blow Hole known as Bamboo Ridge.

"That incident really devastated the other fishermen," Clark said.

They decided to put up a statue of Jizo, a Buddhist deity who protects children and travelers, just above Bamboo Ridge, Clark said. But the statue was vandalized after a few years and was replaced in 1940 by a moss rock bearing a bas-relief of Jizo.

It's still there, Clark said.

The link to history intrigued a pair of ocean safety experts who took the project to heart: Kevin Allen, a lifeguard captain, and Jimmy Barros, who studies injury prevention strategies for the city's Ocean Safety and Lifeguard Services Division.

Using scrap lumber the lifeguards had and painting supplies they bought with their own money, the two men built the first obelisk. They'll put it in the ground themselves, too, sometime this morning.

Shaped like the Washington Monument, it will say "danger" in Japanese and have modern icons the lifeguards use to warn people. They plan to place it in the middle of the path taken by visitors to China Wall.

"I don't know if I can get more specific to the public than that," said Barros, who views signs as a last resort. "The signs don't seem to be doing it."

It has been an especially tragic year along the East Honolulu coastline, Barros said.

But it could have been worse.

Two months after the task force first met, Jasmine Kermmoade, a 19-year-old tourist from Nebraska, stood at Lana'i Lookout posing for a photograph with five friends. A wave knocked them all down, yet only Kermmoade was swept into the ocean.

"It had the potential to be the worst ledge fatality we would ever have had," Barros said. "There were six people and they were all right there. And for one reason or another, she fell one way."

Barros saw the survivors at the hospital afterward and the experience shook him. One of them had jumped into the ocean to try and save Kermmoade.

He became a victim as well. He couldn't save her.

"And the guy who tried to save her," said Barros, "he has to live with that for the rest of his life."

Reach Mike Gordon at mgordon@honoluluadvertiser.com.