What does the triad in the perpetual calendar mean?

In ancient China, the Trinity refers to the combination of heavenly stems and earthly branches. In the perpetual calendar, the trinity usually refers to the combination of the earthly branch of the sun and the earthly branch of the time, the earthly branch of the day and the monthly branch, the time branch and the Japanese branch or the Japanese branch and the annual branch. These combinations are considered to have special peaceful significance and are usually regarded as auspicious signs.