A haura is the lining of a haori, the jacket worn over a kimono. A paper by Ōmori Masao of Kyoto Saga University of Arts describes how splendid designs came to be hidden in it. In the Edo period, sumptuary laws kept people from wearing showy kimono. One of the fashions devised under them was to hide splendid designs in the lining and in the underrobe.
The haura cannot be seen while the jacket is worn. Others see it only when the jacket comes off. The paper calls this the beauty of uramasari, the lining that surpasses the outside.