(H) means Heavy--and refers to B-17s and B-24s.(VH) means Very Heavy--B-29s.
Part of the 5th Bombardment Group "Bomber Barons," the 23rd fought its way across the Southwest Pacific during World War II. The 23rd initially flew Boeing B-17E Flying Fortresses into combat, replacing those with Consolidated B-24 Liberators by early 1943. Long-range overwater missions were the squadron’s forte, and in April 1944 the squadron won its first of two Distinguished Unit Citations for flying the longest overwater bombing mission ever flown to date, some 1,300 miles each way, to bomb the Japanese base at Woleai Island. After winning a second DUC for another long range strike against oil refineries on Borneo on Sept. 30, 1944, the 23rd found itself in the Philippines at the close of the war.