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We propose to directly measure comma for the first time comma the individual masses for the binary black hole candidate MOA-2019-BLG-284. Unlike some previous studies (Sahu+2009 comma 2019 comma Kains+2017) comma we have selected this candidate based on both its large Einstein radius crossing time of 500 days and its relatively small microlensing parallax of 0.038. The combination of these two parameters is much more effective at identifying black hole microlensing candidates than using events with large Einstein radius crossing time comma but no constraint on the microlensing parallax. We also have worked with the microlensing survey groups to remove systematic photometry errors that could contaminate the microlensing parallax measurement. This target is ideal given its very long duration comma clear microlensing parallax signal comma relatively bright baseline magnitude and previous HST observations taken in 2020. Further comma the current best-model gives a total lens mass of virgul10 Msun or more comma with roughly equal mass lens components. If successful comma these observations will complement the groundbreaking work of LIGO comma and open a new window on the population of (pre-merged) binary black holes in our Galaxy.