Staff at the central Kasumigaseki metro station held a moment of silence at 8:00 am and some commuters offered floral tributes at a remembrance stand erected there.
Among the victims were two metro workers killed at the station, which is close to Japan's political heart with many government ministries nearby.
"Our duty is to protect safety every day and we need to ensure people can commute with peace of mind," said area manager Mitsuaki Ota, according to Kyodo news agency.
The attack killed 13 people and sickened more than 6,000, sowing panic among Tokyo's millions of daily commuters.
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Thirteen Aum members, including guru Shoko Asahara, are on death row after being convicted over the subway attack.
Asahara, a near-blind yoga master who preached a blend of Buddhist and Hindu dogma sprinkled with visions of the apocalypse, attracted some 10,000 followers at the height of his popularity.
He developed an obsession with the Nazi-developed sarin gas, becoming paranoid that his enemies would use it to attack him.
In all, nearly 190 members of the cult were charged in relation to the attack.