noun which may take the genitive case particle 'no', na-adjective, noun
formal; orthodox; proper; genuine
Describes something done in the officially recognized, standard, or full-scale manner, as opposed to a simplified or trial version.
本式の手続きを踏む必要がある。
You need to follow the formal procedure.
これは本式な茶会です。
This is a formal tea ceremony.
noun which may take the genitive case particle 'no', na-adjective, noun
in earnest; serious; full-blown
Used when something becomes serious, full-scale, or reaches its peak, often with a nuance of intensity or commitment.
本式の冬が到来した。
Full-blown winter has arrived.
彼は本式に勉強を始めた。
He started studying in earnest.
Compound of 本 (ほん, 'main, real') and 式 (しき, 'style, ceremony, formula'). The exact historical derivation is uncertain, but the combination naturally yields the meaning 'real/formal style'.