Japan's elementary and junior high school students have strong basic academic skills but struggle to solve complex questions, according to this year's nationwide achievement test results, which were released Monday by the education ministry.

Since its launch in 2007, the test has been drawing attention from schools and local governments, as the 47 prefectures are ranked according to their average scores.

But at the same time, some question the necessity of holding the test every year, considering that recent results remain more or less the same.