The magnitude 9.0 earthquake unleashed a wall of water that hit Japan's northeast coast, killing nearly 16,000 and leaving nearly 3,300 unaccounted for, and the country is still grappling with the human, economic and political costs.
In the port of Ofunato, hundreds of black-clad residents gathered at the town hall to lay white chrysanthemums in memory of the town's 420 dead and missing.
"We can't just stay sad. Our mission is to face reality and move forward step by step," said Kosei Chiba, 46, who lost his mother and wife in the disaster.
"But the damage the town suffered was too big and our psychological scars are too deep. We need a long time to rebuild."
The country observed a minute of silence at 2:46 p.m. (0546 GMT), the time the quake struck.
Residents of Ofunato gathered before a makeshift altar with a calm, sun-flecked sea behind them. Ofunato paused again 33 minutes later -- the time when a year ago a 23-metre (75-foot) tsunami engulfed the town of 41,000.
Just a kilometre (half a mile) from Tokyo Electric Power Company's (Tepco) wrecked Fukushima plant, where reactor meltdowns triggered the world's worst nuclear crisis since Chernobyl, residents of the abandoned town of Okuma were allowed back for a few hours to honour the dead.
"It was a wonderful place. If it wasn't for all that has happened, I'd be able to come back. But thanks to Tepco, I wasn't even able to search for the bodies of my relatives," said Tomoe Kimura, 93, who lost four members of her family in the tsunami, two of whom were never found.
Authorities have imposed a 20-km (12 mile) no-go zone around the plant and residents may never be allowed back.
Along the northeast coast, police and coastguard officers, urged on by families of the missing, continue their dogged search for remains despite diminishing chances of finding any.
The Japanese people earned the world's admiration for their composure, discipline and resilience in the face of the disaster while its companies impressed with the speed with which they bounced back.
As a result, the $5 trillion economy looks set to return to pre-disaster levels in coming months with the help of about $230 bill lion earmarked for a decade-long rebuilding effort agreed in rare cooperation between the ruling and opposition parties.
Emperor Akihito, recovering from coronary bypass surgery last month, attended a memorial service in Tokyo's National Theatre and urged people to work together, echoing his unprecedented televised address five days after the disaster.
"I expect many difficulties on the path to recovery. I hope all the people will keep the victims in their hearts and work so that the situation in the disaster-hit areas improves," the 78-year-old monarch said at the televised ceremony.
Prime Minister Yoshihiko Noda, addressing the same event, pledged to work for recovery: "We will fulfill our historic mission of realising the rebirth of this nation."
Yet many people are increasingly disillusioned about the political establishment's ability to tell the truth and rise to the occasion, a deep lack of trust that one commentator called "the fourth disaster of March 11".
Politicians and bureaucrats drew fire for the chaotic response to the Fukushima disaster and a failure to seize the moment to tackle the ills plaguing Japan for over two decades.
"There is no leadership," said Hiroaki Oikawa, 56, another Ofunato resident who lost his two fish factories and his home, speaking on the eve of the anniversary.
After a brief truce, political parties resumed the parliamentary squabbles that gave Japan its sixth leader in five years and now threaten to block an important tax reform and stall other business, including the launch of more independent nuclear watchdog.
Anti-nuclear demonstrations also served as a reminder that many want bolder action than the government's preferred scenario of a gradual reduction in reliance on nuclear power.
"Haven't they realised yet it's unsafe?," said pensioner Sachiyo Katayose, one of about 100 protesters outside Tepco's Tokyo headquarters, where they laid a banner on the pavement reading "Give us back Fukushima".
Tepco, criticised by many for its failure to prepare for the disaster, issued a fresh apology.
"Each and every member of our company and its group remembers March 11 and will work with our all hearts to solve challenges with safety as our first priority," Tepco President Toshio Nishizawa, who marked the anniversary at the plant, said in a statement.
Slow progress in drawing up plans for the tsunami-damaged and radiation-contaminated region is deepening the misery of survivors, about 326,000 of whom are still homeless, including 80,000 evacuated from the vicinity of the Fukushima plant.
While the government declared its reactors had reached "cold shutdown" in December, the country lives under a cloud of anxiety over the long-term health effects of radiation.
The plant's dismantling and the clean-up of an area the size of Luxembourg will take decades at an incalculable cost using technologies yet to be developed.
Taxpayers, facing proposed sales tax increases to help fund the country's debt, will need to cough up tens of billions of dollars to prop up the still politically powerful Tepco.