The following list came from GHQ/SCAP microfich in the National Diet Library. The microfich numbers are AG(B)-01603 D-3 and D-4. The original doccuments were sent from HQ PHIL-RYUKYUS to CINCFE on Dec 16, 1947.
The following figure is a call area map at that time, extracted from QST Jan 1947 (TKS TO JA1BWA).
These 1×3 format call signs above had used until Dec. 31, 1948, and then changed to 2×2 format. Here is a sample of the reallocation order, which states to change Major R. M. Lantz's call sign from J2GHQ to JA2AV (Microfich# AG(B)-01955 A-13).
Unfortunately, "Chart of Amateur Districts" and "List of Authorised Amateur Stations" are not attached in the microfich....