The survey covered responses of undercover customers visiting the banks' main branches from June to July 2010. Ratings were based on different client service criteria, including office management, knowledge about products, quality of service, and waiting periods.

"Market leadership is about delivering best-in-class value propositions. Innovation means bringing fresh value to customers. Our Japanese team has delivered a new digital 'smart banking' experience tailored to each specific customer segment... clearly they love it and we're on a new growth trajectory as a result," Stephen Bird, chief executive of Citi Asia Pacific, said in a statement.

Citibank Japan in April opened two new retail banking branches in Nihonbashi and Marunouchi, which are both considered high-traffic areas. These are the first full-service "smart banking" branches in Citi's global network. More of these branches are on the way within the next 12 months, bringing its total in Japan to 35.