2005 is the year which they began to debut in Japan, but before that they try their luck with China first, because in January 2005, they released Tri-Angle Chinese version.
They officially debut in Japan on April 27 2005 with single "stay with me tonight" but their debut in Japan not that successful, as we know they debut as Jpop not Kpop also they still can’t speak Japanese.
In June they returned to Korea and released a single Hi yaya, where the music video of this song taken in Bora-bora and it was the first time they went there,
after that Bora-bora become Junsu favorite place even until now.
At JYJ Membership week 2012, Junsu said that when in Bora-bora they promised that they would go back there again someday and Yuchun adding that they are essentially promises to go back there again with their partners, kekekeke.
I think there are strong reasons why they want to come back with a partner, because at that time in Bora-bora they peek a newlywed couple who are tet sensor ----- ----- LOLL
In September before they release their second Korean album, at Sept 6th 2005 Jae's knee got injured during rehearsal, after that he got surgery on Sept 8 & Sept 10 and He had to be on stage 2 days after surgery for rising sun show case, aww Poor my Jeje, what a company is that, at lease let him rest, T.T Jaejoong lost 8kg due to knee injury
During his injury Jaejoong also for the first time get contact with his birth mother, his mother called him first (his mother said, she got jaejoong phone number from female student when she bought Jaejoong storybook, why I think that female student is sasaeng and after that they met.
Ah Before jeje got injury, in August Junsu was rushed to the hospital because of high fever, poor our boys
September 12th, 2005 is the official date released their second album. Because of the injury Jaejoong could not participate for a dance scene in the rising sun MV, this year they also received an award at the People's Choice Award at the 2005 Mnet KM Music Video Festival where the epic scene of Yoochun crying uncontrollably got recorded
SM really made them like slaves not so far after rising sun promotions in Korea in November they returned to Japan and released their next single “my destiny” and in December they returned again to the Korean to join SM xmas album.
On Dec. 3rd at the Seoul Olympic Park where the VOICES FOR CHILDREN Concert was held, Jaejoong said "I can walk but I'm not able to dance yet." God can’t imagine he is back and forth between Korea n Japan promoting with his knee