Legend has it that En no Gyōja (an ascetic wanderer who lived a generation prior to Kūkai, 634-701, and is claimed, incorrectly, to be the founder of Shugendō) subdued a fiery dragon here on the mountain and then founded the temple. A hundred years later, Kōbō Daishi returned to find that it was once again terrorizing the local inhabitants and was causing a great deal of damage to life and property in the area. As Kōbō Daishi ascended the mountain, the dragon's flames threatened to engulf him, but he extinguished them by forming the mudra of Turning the Wheel of the Dharma with the aid of Kokūzō Bosatsu. He was able to seal the dragon in a cave and carved two statues to guard the entrance. For this reason the temple is called Shōsanji. The mountain itself is called Marozan from the Sanskrit word for water (Vari) — subduer of flames.

Among the temple's treasures is a letter from Emperor Daigo. Also, on the summit of the mountain is a small stone sanctuary enclosing a statue of En no Gyōja which memorializes his victory over that trouble causing dragon.

Of interest is the tomb of Emon Saburō at a small shrine two miles down from the temple.

If you are walking to the Bangai Temples as well, don't go directly to Temple 13 from here. Go from Temple 12 to Bangai Temple 2 and then visit Temples 16, 15, 14, & 13 in reverse order. After Temple 13, go on to Temple 17. While this means that you will still have to backtrack a little, it is much less of a backtrack than going from Temple 16 to Bangai Temple 2 and then to Temple 17 which is what you would do if you visited them all in numerical order.

In 2005, i didn't skip Temple 17 after leaving Bangai Temple 2. Instead, after Bangai 2 i visited Temples 17, 16, 15, 14, and then 13 in that order, arriving at Temple 13 just before they closed for the night. The next morning, i left the henro trail (Whatever that means. See my comments in my 2005 diary on Tuesday, April 12) and just followed Highway 208 east. You'll turn on to another highway after a while, and then leave the main road to take a shortcut over a river and through a small housing development, but sooner or later you'll catch up with the henro trail again on the south side of Tokushima City. This worked very well and is what i recommend, but it assumes you can read Japanese well enough to follow the road signs and speak it well enough to ask directions as needed.