The tour marked one of the final stages of the State Visit.
The Emperor was also presented with five artworks by Kew’s resident botanical illustrator Masumi Yamanaka.
He has worked at Kew since 2006 and his detailed illustrations aid scientific efforts to describe new species of plants.
The tour of Kew, which marked one of the final stages of the State Visit, began in the historic Temperate House where the Emperor was greeted by Richard Deverell, OBE, director of RBG Kew.
Richard said: “We were honoured to welcome His Majesty the Emperor to the Royal Botanic Gardens, Kew. We have had a longstanding and close relationship with Japan which can be seen through beautiful structures in our landscape as well as in our living collections, economic botany and art collections. In 2021 we celebrated the relationship through a wonderful month-long Japanese festival in the Temperate House. We are especially proud too of the scientific links we have through our Millennium Seed Bank in Wakehurst which includes important conservation work under the Global Tree Seed Bank Programme, amongst other achievements.”