2017.04.03. 일반우표(330원)

On April 1, 20147, the price of each definitive postage stamp will increase by 30 Korean won to 330 won for first-class mail weighing 5 to 25 grams.

Korea Post will of course make new stamp available on the same day.
The most commonly used 330-won first-class definitive stamp will feature the symbol of Korea, the Taegeukgi.