TOKYO -- Private equity first made Japanese headlines in 2000, when Ripplewood Holdings of the U.S. bought the nationalized Long-Term Credit Bank of Japan, now Shinsei Bank.

The floodgates had not exactly been opened, but a number of overseas investment funds followed Ripplewood to Japan. In 2004, the Carlyle Group was part of a joint venture that acquired DDI Pocket, a wireless carrier whose technology never really caught on, for 240 billion yen ($2.35 billion). DDI Pocket later became known as Willcom.