This is the Japanese Mahonia or Hiragii Nanten or Mahonia japonica (in Japanese) and is in bloom right now. It is native to Japan and Korea.
See the variation in the foliage coloring. These photos were all taken of the same plant on the same day. This plant likes partial shade, moist, well-drained and acidic soil. Look at the fantastic photo of autumn colours that the Mahonia can give at this link.
It will be followed by beautiful blueberry-like berries.
NATURE IN JAPAN 