The pine forest is stretching like an arc of a rainbow along the Karatsu Bay That is "Niji-no-Matsubara" of the doorway in karatsu. Terasawa Shimanokami Hirotaka,the first lord of karatsu Clan, started planting the pine trees on dune along the coastline for protection against the winds and tides. It is said that nearly one million pine trees cluster together for 5km in length, 1km in width. At present, The “Niji-no-Matsubara” is considered one of the three most beautiful pine forests in Japan and designated as scenic beauty spot.
The Niji-no-Matsubara was chosen as the 5th by the vote of TV program "the scenery of Japan to be left in the 21st century