Antique Korean Teaching "Coin" or "Charm". VERY RARE. Excellent Condition

Description

Korean coin like charm used for teaching children Chinese script.
The Chinese characters appear to be written in a very ancient form of seal script known as “bird-worm seal script” (鸟虫篆).
The apparent purpose of the charm is not to promote good luck or provide protection but rather to teach Chinese characters.
According to “The Korean Coins and Banknotes Catalogue”  (大韓民國貨幣價格圖錄), the inscription is read clockwise beginning at about the 8 o’clock position as:
水得女汝, 月於日明
shui de nü ru, yue yu ri ming (Chinese pronunciation)
These charms are incredibly rare. There is one in the British Museum (# 1974,0509.31)
This charm apparently did not exist prior to the Japanese occupation of Korea.  The earliest record of its existence seems to date from the 1920’s in a rubbing from a Korean collector known as “Li De Zhuang”. There is a suggestion that hidden within the Korean translation of the Chinese is an anti-Japanese statement.