Which almanac is the most accurate?

The auspicious parts of the calendar of Xie Fangshu (Yellow Calendar) are not arranged by the same country, but independently. Due to different methods, bases and bibliographies, the authoritative works of choosing auspicious days are Xie Fang Shu in Qing Dynasty and Gan Longyu's inscription and postscript. The yellow calendar, also known as the old yellow calendar and the imperial calendar, is an almanac based on the China lunar calendar.