This weapon is a myth. It does not exist.
Initially, when Yakuza Crate was released, Manrikigusari Chain was rumored to be one of the crate loots. Various fan websites reported that the stats were 40 Attack 10 Defense. However, no one was able to produce the image.
Mafia Wars Wiki has checked and confirmed that Manrikigusari Chain does not exist at all.
See also: Tessen Fan