Adam Liaw explores Japan's high-energy financial centre, Osaka, and finds the world's best fast food, a sumo wrestler turned chef and soba noodles to die for.

In Japan's southern islands, Kyushu and Shikoku, Adam Liaw finds a vibrant, warm culture where old ladies use iPads to harvest the forests, organic farmers grow fruit for their pigs, and the cuisine is as fascinating as its people.

In this, the final episode of Adam Liaw's culinary expedition through Japan, we meet the people of Okinawa and discover an eclectic cuisine derived from Chinese, American, Thai, Japanese and Korean influences, and learn the secret to long life.