Today is a day that all Japanese people - and many around the world - will never forget. On this day 12months ago Japan was hit by a huge magnitude 9.0 earthquake - the biggest to ever strike Japan, and the world's fifth largest since modern records began in 1900.
The quake caused a massive tsunami - sparking a nuclear disaster at a power plant - that killed 15,850 people, injured 6,011 others and left a further 3,287 people missing.
For safety reasons many people are still staying away from the disaster zone, on the east coast of the Tohoku region of the Japanese island of Honshu, but some are going there to help survivors. Hongkonger Louis Choi Ka-fai is one of them.
'I was sad about what happened in Japan and I wanted to help,' says the 31-year-old, who runs his own IT business.
Choi did not hesitate to volunteer to work as a photographer for the Hong Kong charity Post Crisis Counselling Network (PCCN) after spotting a recruitment advertisement on the organisation's website. He joined a team of counsellors that made five, week-log trips last year to Iwate, Hanamaki, Rikuzentakata, Minamisoma and Sendai, which were affected by the tsunami. Each visit was a highly emotional experience.
'In a relief shelter, I met an old lady who was looking at some photographs,' he says. 'I asked her who the people were in the photos and she said they were her grandchildren. Later, I learnt that her grandchildren had been killed; she'd just gone to the funeral.