A banknote issued by the Việt Minh for circulation in the Democratic Republic of Viet-Nam (North-Vietnam). 
<p>P-24a D-10Aa 20 Dong 1947 
No watermark 
</p><p>P-24b D-10Ac 20 Dong 1948 
</p>
Watermark very hard to see (should be Circle with star).
The Việt Minh.
<a rel="nofollow" class="external text" href="http://art-hanoi.com/collection/vnpaper/ho20d48.html">North Vietnam 20 Dong 1947-48</a> (Art-Hanoi).