Lin Rong, 27, had
previously been deported from Japan for overstaying her visa. She was
only discovered when she was arrested on separate charges.
Tokyo police said she had paid $15,000 (£9,000) to have the surgery in China.
It is Japan's first case of alleged biometric fraud, but police believe the practice may be widespread.
Japanese police suspect Chinese brokers of taking huge sums to modify fingerprints surgically.
Local media reports said Ms Lin had undergone surgery to swap the fingerprints from her right and left hands.
Skin patches on her thumbs and index fingers were removed and then re-grafted on to the matching digits of the opposite hand.
Japanese
newspapers said police had noticed that Ms Lin's fingers had unnatural
scars when she was arrested last month for allegedly faking a marriage
to a Japanese man.
The apparent ability of illegal migration
networks to break through hi-tech controls suggests that other
countries who fingerprint visitors could be equally vulnerable - not
least the United States, according to BBC Asia analyst Andre Vornic.
By BBC News online, 7/12/10