Emperor Akihito released from hospital

Japan's Emperor Akihito has made his first public appearance since undergoing medical tests on his heart.

The 77-year-old royal is reported to have been diagnosed with arteriosclerosis -hardening of the arteries - in his cardiac blood vessels during the check-up at the University of Tokyo Hospital last week (11.02.10) but it didn't stop him from making an appearance at the National Diet Library in Tokyo on Monday (14.02.11).

The emperor - accompanied by Empress Michiko - was said to be in good spirits as he viewed a digital archive system showing old documents such as a handwritten encyclopaedia of fish dating from the Edo Era from the early 17th to late 19th centuries.

In the past year, the emperor has cut back on official duties for health reasons and has not made any foreign trips in the past 12 months.

Emperor Akihito has a history of heart problems and was found to suffer from an irregular heartbeat in 2008.

Royal aides said he was suffering from the condition supraventricular arrhythmia - which causes a faster heart rate and inflammation to the stomach - due to stress.

In 2003, the royal also underwent surgery at the same hospital to remove prostate cancer and has since been undergoing hormonal treatment to stop it returning.

At the time his son, Crown Prince Naruhito, temporarily took over his official duties as it was the first time he had left the palace grounds to be treated in a public hospital.