Emperor Akihito took the throne at the age of 55, following the death of his father. He was the first to be enthroned under the post-war Constitution that defines the role as a "symbol of the state."
After ascending the throne, he would seek a new style for the Imperial family that befits the modern age.
He had his first chance to show what he meant when a volcano erupted in southwestern Japan in 1991. The imperial couple visited an evacuation center and knelt next to the victims.
From then until today, whenever a natural disaster hits Japan, the couple takes time to comfort the victims.
They were on the scene after an earthquake rocked Kobe in 1995. And when a massive quake and tsunami struck the northeast in 2011, they travelled to the devastated region many times over the next few weeks.
The Emperor and Empress have also shown concern about socially vulnerable people. On many occasions, they have visited the elderly and people with disabilities.
The Emperor has continued to think about the effects of World War Two in and out of Japan. The couple visited Okinawa 11 times to see where one of the final and fiercest battles was fought, and where more than 200,000 people died.
The Emperor has also mourned people who died on battle grounds on Pacific islands, paying tributes to both sides.
In August 2016, Emperor Akihito made a surprising announcement: He expressed his apparent wish to step down.
"I am already 80 years old, and fortunately I am now in good health," he said. However, when I consider that my fitness level is gradually declining, I am worried that it may become difficult for me to carry out my duties as the symbol of the State with my whole being as I have done until now."
The Emperor's statement sparked a flurry of government activity. There was no rulebook for what should come next. So a panel had to be set up to figure out how to handle an abdication.
In January 2017, the panel released a report recommending a one-time provision for abdication. After lengthy discussion in the Diet, the bill was approved and the plans got the green light.
Emperor Akihito reflected on his era at a press conference in December 2018, just before his 85th birthday.
He said: "I have believed it is important not to forget that countless lives were lost in World War Two and that the peace and prosperity of post-war Japan was built upon the numerous sacrifices and tireless efforts made by the Japanese people, and to pass on this history accurately to those born after the war. It gives me deep comfort that the Heisei Era is coming to an end, free of war in Japan."
In February, Japan commemorated the Emperor's 30th year on the throne. He expressed gratitude to the people, and said: "It's fortunate that I have been able to accomplish my duties as Emperor with the help of the people."