The 34-year-old, who has modelled underwear in the past, was unveiled by the first division side and quickly had his new team-mates gushing about his kicking motion.
"His motion is always the same but he has puts all sorts of different movement on the ball," goalkeeper Kaito Yamamoto told Japan's Nikkan Sports newspaper.
"His power and control are incredible," he added after getting a first-hand look at the shaven-headed new arrival.
"He's not at 100 percent yet but he is going to be give goalkeepers a lot of trouble."
Ljungberg, who captained the Swedish national team until announcing his international retirement after Euro 2008, is set to give a news conference on Thursday.
He was a member of Arsenal's "Invincibles" - who won the 2003/04 English Premier League title without being beaten - during nine hugely successful years in North London.
Ljungberg joins a list of high-profile players to make their swansong in the J-League since it was launched in 1993, including Zico, Gary Lineker and Dragan Stojkovic.
The Swede was capped 75 times and scored 14 goals for his country. He also had spells at West Ham United and in American Major League Soccer before joining Celtic last season.
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