Title : Science Postage Stamps Series (3rd Issue)
Stamp Serial#
 1533 
KPC#
 C-1161 
MICHEL#
 1557 
StanGib#
 1833 
Scott#
 1480 
Date of Issue
 04/21/1988 
Quantity
 2,000,000 
Denomination
 80 won 
Design
 A Water clock 
Designer
 Kim, Yong-gi 
Image Area
 22mm*47mm 
Perforation
 13 
Sheet Composition
 Sheet of 20(4*5) 
Paper
 White Unwatermarked
Print
 Korea Security Printing and Minting Corporation 
Description
The Ministry of Communications has been issuing science postage stamps in serial form since 1986, featuring our ancestors' scientific inventions and creativeness so that we of today will inherit and develope their scientific-mindedness.

The scientific quest of our forethers for a time-measuring device is the theme of this third set of science postage stamps, which consists of the following two kinds:
Water clock (chagyokru, National Treasure No. 229).
Invented in 1434 by Chang Yongshil and Kim Bin, this water clock was devised to signal time automatically, and operated with remarkable precision, contributing greatly to measuring time.

Sundial (angbuilgu).
This sundial, part of a series of astromical observation equipment completed during King Sejon's reign (1418-1450), had a variety of functions and sophistication incomparable with any previous device. It was installed on a big bridge crossed by a large number of people, thus becoming the first public clock of our country.