These granite flagpole supports (danggan-jiju) are located just beyond the Iljumun gate. they are 4.8m (15.75ft) tall, and date to the 9th century, according to the sign. There are actually two ways of using danggan. With one pair, as here, a streaming narrow banner is hoisted up the flagpole to announce special events. With two pairs, a horizontal pole is suspended between two flagpoles. Banners painted with Buddhist images are draped over the horizontal pole, to provide a focus of worship on special days when there are too many worshipers to fit inside the temple halls1.
1This was explained by a temple cultural guide. These are volunteers, usually retirees with interest in a particular cultural site, who are trained locally and certified under a national program.