The Bank of Japan on Monday raised its assessment for five of the country's nine regional economies amid strong exports to Asia.

The BOJ used the word "expansion" to describe six of the regional economies, the most since it began releasing the Sakura Report, named for its cherry blossom-colored cover, in 2005.

Reasons for the assessment upgrade included strong demand for electronic components such as those used in smartphones as well as manufacturing equipment in China, Taiwan and Southeast Asia.