HONOLULU — As the sun broke from behind the billowy clouds hanging over Oahu’s Koolau mountains, a seven-member detail of military personnel transferred five coffins one recent morning, disinterred from two grave sites marked “unknown,” at the Punchbowl, the National Memorial Cemetery of the Pacific here in the shallow crater of an extinct volcano.

In the distance, Punchbowl’s twin, Diamond Head, reached into the southern sea. Off to the west was the flat, estuarine waterway called Pearl Harbor, where the men in the coffins died 73 years ago.

Silently, the detail draped each coffin with a fitted American flag, saluted and placed the coffins into panel trucks. An honor platoon, the five hard-hatted cemetery workers (all veterans) and a sprinkling of other military personnel held their salutes until the trucks were out of sight.

“We’re not ‘mission complete’ until we return them home,” Lt. Col. Melinda F. Morgan, a director of public affairs for the Defense P.O.W./M.I.A. Accounting Agency, said of the remains of 388 sailors who died aboard the battleship Oklahoma during the surprise attack on Pearl Harbor.

Eventually, 61 coffins from 45 grave sites will be dug up, Colonel Morgan said, and taken to laboratories that over the next five years will use DNA and dental records to identify the remains, the names of which have long been engraved on a memorial near Pearl Harbor.

The process of searching for and identifying troops missing from World War II has been going on since the fighting ended 70 years ago, but the latest efforts have taken on a sense of urgency as time passes and the number of men and women who served who are still alive dwindles. The Oklahoma identifications are also a tribute to the tenacity of a Pearl Harbor survivor.

“There are unknowns around the world,” said James Horton, director of the national cemetery in Honolulu, where 2,760 unidentified troops are buried, 1,061 from Pearl Harbor. “What makes identification very difficult is the severity of what happened, which may have made things messy, and how much more fighting there’s going on in those areas.”

“The reason they went for the Oklahoma unknowns is there is a known set of them, a fairly finite set,” he said.

Of the eight battleships hit by torpedoes and bombs that Sunday in 1941, only the Oklahoma and the battleship Arizona were damaged beyond repair. The Arizona — where almost half of the more than 2,500 people killed in the attack died — rests below a memorial at Pearl Harbor. The Oklahoma, which was hit by nine torpedoes and capsized, was brought up two years later; the time it spent underwater made identifying the victims more difficult.

The bodies recovered from the Oklahoma were buried throughout Oahu and later transferred to the Punchbowl in 1949 after the cemetery was dedicated. Some of the remains ended up in separate coffins. “In World War I and World War II, there were decisions made, partly because of the number of casualties, to inter those veterans as they fell,” Mr. Horton said.

The push to identify the Oklahoma unknowns began modestly as a quest by a Pearl Harbor survivor, Ray Emory, for better grave markers.

When Mr. Emory, 94, who manned a machine gun on the port side of the light cruiser Honolulu during the attack, visited the Punchbowl in 1990, a cemetery worker could not tell him where to find the sailors from the Oklahoma.

That began a quest for headstones that would distinguish Pearl Harbor unknowns from those who died in other wars or other battles. Mr. Emory then wondered if he could somehow single out the name and grave for one Oklahoma victim.

His curiosity sent him on what would become a serpentine venture through stacks of burial records. “There was more of a story after Dec. 7 than Dec. 7, really,” he said.

One file contained a list of names, ranks and burial numbers of 27 servicemen before their reburial at the Punchbowl. Using that information, Mr. Emory located the graves of those men, and in 2003 the military agreed to exhume five of the bodies he had identified.

Encouraged by the result, Mr. Emory reached out to family members of the remaining 22 unknowns, asking them to pressure state and national lawmakers. A letter to the Pentagon in 2014 from Senators Kelly Ayotte, Republican of New Hampshire, and Chris Murphy, Democrat of Connecticut, urging the disinterment and identification of the Oklahoma unknowns went nowhere.

But a similar letter sent in February paid off, and in April the deputy secretary of defense, Robert O. Work, announced plans to disinter and identify the unknown remains from the Oklahoma. The work began in June.

“It was quite amazing,” Mr. Emory said. “I thought they would dig up the rest of the 22 of the first 27, but I didn’t realize they would go back and dig out the rest.”

The identifications are usually done using dental records or by DNA testing, said Michael Linnington, a retired Army lieutenant general and director of the Defense P.O.W./M.I.A. Accounting Agency. The laboratory in Honolulu will focus on dental records, he said, while tests comparing the victim’s DNA with that of a relative would be performed at a laboratory in Omaha, Neb.

There are limitations. A grave site containing commingled remains may be dug up, the announcement said, only if it is likely that evidence can determine identities for 60 percent of the remains. A grave containing a single unknown may be disinterred only if there is a 50 percent likelihood that the remains can be identified.

Remains that cannot be identified will receive a full military honors burial, Colonel Morgan said. Near the time of that burial, Colonel Morgan said the Defense P.O.W./M.I.A. Accounting Agency would determine what to do with remains without surviving or identifiable relatives.

For some families, the long wait may soon be over. Thomas Gray of Guilford, Conn., hopes to bury his second cousin, Edwin Hopkins, in a family plot in Keene, N.H., next spring.

“It was like an open wound,” Mr. Gray said of the time before Mr. Hopkins was identified earlier this year.

Mr. Hopkins, a 19-year-old fireman third class from Swanzey, N.H., was initially buried in Halawa Cemetery in Hawaii, and then reburied at the Punchbowl in 1949. He had enlisted a year before the attack; his brother, Frank, was already in the Navy, and he had hoped to serve with him, Mr. Gray said. (Family serving together was not uncommon; 23 sets of brothers, for example, died on the Arizona.)

Mr. Hopkins’s mother, Alice, who died in 1987, always believed her son would return home, Mr. Gray said, and in 1943 she had Edwin’s name engraved on a headstone in the family plot.

Mrs. Hopkins never talked about her son, Mr. Gray said, and “my father would just say he was a nice boy.”

Kenneth Schultz, whose uncle, Kenneth Lyle Jayne, also died on the Oklahoma, recalls similarly painful memories.

“For all my life, I’ve wondered what he’s like. My mother talked about him all the time when we were kids,” Mr. Schultz, of East Patchogue, N.Y., said. “She used to tell me I was a lot like him, that I’m left-handed like him. She’d say, ‘I wish you could’ve met him.’ ”