Japan’s monetary policy underwent a historic shift last month under the leadership of Bank of Japan Gov. Kazuo Ueda, who marks one year on the job on Tuesday, as the central bank decided to scrap negative interest rates to implement its first rate hike in 17 years.

The move highlights how the BOJ is finally taking a step away from its decadelong aggressive monetary easing, which was rolled out by Ueda’s predecessor, Haruhiko Kuroda.

Looking back at his first year, some central bank watchers have praised Ueda for the way in which he has navigated the transition toward monetary policy normalization. But they also pointed out that there are mounting challenges ahead for the Ueda-led BOJ as Japan begins to contend with positive interest rates.