一石六斗

Etymology
Based on a pun on the term written using the ateji  of. Literally, the phrase means “one koku and six to”, a measure of volume roughly equivalent to 288 liters and equal to 16 to.

Figuratively, refers to seeing something once, being happily surprised and saying, and then seeing it again and saying はっと once more in disappointment. はっと twice would be 8 to + 8 to = 16 to, or 1 koku and 6 to.

Noun

 * 1)  being surprised twice
 * 2)  more specifically, describes the appearance of a woman who has a beautiful figure from behind but has an ugly face