At memorial observances in Tokyo and in barren towns along the northeastern coast, those gathered bowed their heads in a moment of silence marking the moment, at 2:46 p.m. on March 11, 2011, when the magnitude 9.0 earthquake - the strongest recorded in Japan's history - struck off the coast.
"I pray that the peaceful lives of those affected can resume as soon as possible," Emperor Akihito said at a somber service at Tokyo's National Theater.
Japan has struggled to clean up radiation from the Fukushima Dai-Ichi nuclear plant, whose reactors melted down after its cooling systems were disabled by the tsunami, and rebuild lost communities along the coast. A new government elected in December has vowed faster action, but has yet to devise a post-disaster energy strategy - a central issue for its struggling economy.
About half of those displaced are evacuees from areas near the nuclear plant. Hundreds of them filed a lawsuit Monday demanding compensation for their suffering and losses.
Throughout the disaster zone, the tens of thousands of survivors living in temporary housing are impatient to get resettled, a process that could take up to a decade, officials say.
"What I really want is to once again have a 'my home,' " said Migaku Suzuki, a 69-year-old farm worker in Rikuzentakata, who lost the house he had just finished building in the disaster. Suzuki also lost a son in the tsunami, which obliterated much of the city.
Farther south, in Fukushima prefecture, some 160,000 evacuees are uncertain if they will ever be able to return to abandoned homes around the Fukushima Dai-ichi nuclear power plant, where three reactors melted down and spewed radiation into the surrounding soil and water after the tsunami knocked out the plant's vital cooling system.
The lawsuit was filed by a group of 800 people in Fukushima against the government and Tokyo Electric Power Co., the utility that operates the now-closed Fukushima plant. It demands an apology payment of 50,000 yen ($625) a month for each victim until all radiation from the accident is wiped out, a process that could take decades.
Evacuees are anxious to return home but worried about the potential, still uncertain risks from exposure to the radiation from the disaster, the worst since Chernobyl in 1986.
While there have been no clear cases of cancer linked to radiation from the plant, the upheaval in people's lives, uncertainty about the future and long-term health concerns, especially for children, have taken an immense psychological toll on thousands of residents.
"I don't trust the government on anything related to health anymore," said Masaaki Watanabe, 42, who fled the nearby town of Minami-Soma and doesn't plan to return because the radiation in the ground is too high.
In Kawauchi, one of many towns with varying degrees of access restrictions due to radiation, village chief Yuko Endo is pinning his hopes on the success of a long decontamination process that may or may not enable hundreds of residents to return home.
Much of the area is off-limits, though some restrictions gradually are being lifted as workers remove debris and wipe down roofs by hand.
Many residents might give up on returning if they are kept waiting too long, he said.
"If I were told to wait for two more years, I might explode," said Endo, who is determined to revive his town of mostly empty houses and overgrown fields. "After spending a huge amount of money, with the vegetable patches all cleaned up and ready for farming, we may end up with nobody willing to return."
A change of government late last year has raised hopes that authorities might move more quickly with the cleanup and reconstruction.
Since taking office in late December, Prime Minister Shinzo Abe has made a point of frequently visiting the disaster zone, promising faster action, and plans to raise the long-term reconstruction budget to 25 trillion yen ($262 billion) from 19 trillion yen (about $200 billion).
"We must speed up the reconstruction effort for the survivors who are living with heart and soul," Abe said in an address at the memorial service. "I believe that would be a way to serve justice for the perished, whose spirits are looking after us from the heaven."
Hopes for a significant improvement may be misplaced, said Hiroshi Suzuki, chairman of the Fukushima Prefectural Reconstruction Committee.
"There have been no major changes by the new government in response to the nuclear accident, though the budget has been increased," he said. "If the reconstruction budget continues to serve as a tool for expanding public works spending, then I believe local societies and economist will be undermined."
Another lingering problem is discrimination against evacuees from Fukushima.
Watanabe, who used to work for a company maintaining the nuclear plant's lighting systems, said his sons are sometimes shunned or taunted by classmates who say things like, "Don't come near me. You're radioactive."
Many fear their children will find it hard to find spouses due to worries over potential long-term harm from radiation, Suzuki said.
The struggles to rebuild and to cope with the nuclear disaster are only the most immediate issues Japan is grappling with as it searches for new drivers for growth as its export manufacturing lags and its society ages.
Towns impatient to rebuild face the stark reality of dwindling, aging populations that are shrinking still further as residents give up on ever finding new jobs in areas where the backbone industries of fish processing and tourism were wrecked by the tsunami or paralyzed by the nuclear crisis.
Decommissioning the nuclear plant could take 40 years as its operator works on finding and removing melted nuclear fuel from inside its reactors, disposing of spent fuel rods and treating the many tons of contaminated waste water used to cool the reactors.
Japan's 54 nuclear reactors shut down for regular inspections and then special tests to check their disaster preparedness, though two restarted last summer, to help meet power shortages. While polls show the majority of Japanese remain opposed to restarting more nuclear plants, Abe's government has indicated it favors restarting those that meet revised safety standards.
The government looks likely to back away from a decision to phase out nuclear power by the 2030s: Abe says it may take a decade to decide on what Japan's energy mix should be.___
Associated Press writers Malcolm Foster and Mari Yamaguchi in Tokyo and Emily Wang in Kesennuma, Japan, contributed to this report.