An example of the close cultural contact between Korea and Japan is provided by a tomb in Nara Prefecture, discovered in 2005, and made from Baekje-style bricks with earthenware dated to the time when Silla united the Korean Peninsula.
Kunihiko Kawakami, a professor of archeology at Kobe Yamate University, said, “It’s highly likely the tomb is that of the Baekje king Changseong, who fled to Japan with his father Seongwang in 631 and died in 674.” Father and son were unable to return because of Baekje’s fall in 660.”
Ancient Tomb of Exiled Korean King Found in Japan
An education board in Japan’s Nara Prefecture said Thursday it has discovered a luxurious tomb most likely that of a king from Korea’s ancient Baekje kingdom who went into exile in the island country.
The tomb is in the ancient Kazumayama burial grounds, often referred to as “the kings’ ravine,” which house many royal tombs including Takamatsuzuka.
It is a stone chamber built with flagstone-like bricks in the Baekje style, and judging from the earthenware excavated from it is likely to have built in 660-670 B.C., the Asukamura Education Board said.
Kunihiko Kawakami, a professor of archeology at Kobe Yamate University, said, “It’s highly likely the tomb is that of the Baekje king Changseong, who fled to Japan with his father Seongwang in 631 and died in 674.” Father and son were unable to return because of Baekje’s fall in 660. (englishnews@chosun.com )
Heritage of Japan 
The Baekje king Changseong did not fllee to Japan with his father Changseong in 631 and died in 674, but he go to the same country japan as Baekje Because Baekje kingdom and japan are exactly same country having same ancesters.