understanding, comprehension / appreciation

we; us

(respectful) current emperor's deceased paternal father / (respectful) grandfather

to study / to learn

the above / the top (position or direction) / the surface of / superior in skill, age, level, etc.

in addition; furthermore / on top of (which)

understand, comprehend / appreciate

important, significant

importance, consequence, significance

the past (period of time that has already happened)