Looks like a Philipine fifty cent piece. I have never seen one like it. With the date (1944) could it be a war time currency, possibly to be used on a military base. Just a guess. Nice coin.
During the war years, the Manila Mint was not operational, and no coins circulated in The Philippines. When the Americans retook these islands from Japan beginning in October, 1944, they carried with them new coinage of the USA/Philippines series. These were coined at the Philadelphia, San Francisco and Denver Mints (the latter bore a D mintmark). The minor pieces were of slightly different standards, a concession to the shortage of certain metals during the war years. These coins quickly replaced the Japanese “funny-money” scrip and Filipino/American guerrilla notes then in use, and they remained a legal tender for many years after the islands became the independent Republic of The Philippines, July 4, 1946.