This SCAPIN was issued on June 22nd 1946. It blocked
resources including Liancourt Rocks and the line is famous as so-called MacArthur Line.
You can read the original document at the following website:
It excluded Liancourt Rocks from Japanese territory and Rhee Syngman based his thought on this MacArthur Line when he drew the same line (Rhee Syngman Line) in 1952 just before the conclusion of the Peace Treaty. But was this President Rhee's claim legitimate?
There is a note at the very end of the SCAPIN:
“5. The present authorization is not an expression of allied policy relative to ultimate
determination of national jurisdiction, international boundaries
or fishing rights in the area concerned or in any other area”.
It clearly says that the MacArthur Line is not defining the territory. So it is questionable to draw the same line and occupy Liancourt Rocks by force on the ground that USA drew the same line in 1946.
The SCAPIN was abolished on September 19th 1949 by SCAPIN 2046.