Translation guide
Nidan verbs are a historical class of Japanese verbs that follow a two-base conjugation pattern. They are the predecessors of modern ichidan (ru-verbs) and some godan verbs. This guide explains their conjugation for learners reading classical or pre-modern Japanese.
Explain what nidan verbs are and their historical context
Nidan verbs (二段動詞) are verbs that have two distinct vowel-stem forms in classical Japanese: the mizenkei (未然形) and renyōkei (連用形) end in one vowel, while the shūshikei (終止形), rentaikei (連体形), izenkei (已然形), and meireikei (命令形) end in another. They are divided into kami-nidan (upper bigrade, ending in -i) and shimo-nidan (lower bigrade, ending in -e). Most modern ichidan verbs evolved from shimo-nidan, while some godan verbs evolved from kami-nidan.
In classical Japanese, 'oku' (to get up) was a kami-nidan verb, conjugating as mizenkei 'oki', renyōkei 'oki', shūshikei 'oku', rentaikei 'okuru', izenkei 'okure', meireikei 'okiyo'.
Show the conjugation tables for kami-nidan and shimo-nidan verbs
Kami-nidan verbs have stems ending in -i. The base forms are: Mizenkei: -i, Renyōkei: -i, Shūshikei: -u, Rentaikei: -uru, Izenkei: -ure, Meireikei: -iyo.
起く：起き（未然）、起き（連用）、起く（終止）、起くる（連体）、起くれ（已然）、起きよ（命令）
oku: oki (mizen), oki (renyō), oku (shūshi), okuru (rentai), okure (izen), okiyo (meirei)
Shimo-nidan verbs have stems ending in -e. The base forms are: Mizenkei: -e, Renyōkei: -e, Shūshikei: -u, Rentaikei: -uru, Izenkei: -ure, Meireikei: -eyo.
食ぶ：食べ（未然）、食べ（連用）、食ぶ（終止）、食ぶる（連体）、食ぶれ（已然）、食べよ（命令）
tabu: tabe (mizen), tabe (renyō), tabu (shūshi), taburu (rentai), tabure (izen), tabeyo (meirei)
Explain how nidan verbs evolved into modern ichidan and godan verbs
Most shimo-nidan verbs became modern ichidan (ru-verbs) by losing the -u ending and adding -ru. For example, 食ぶ (tabu) → 食べる (taberu). Kami-nidan verbs often became godan verbs ending in -iru, or in some cases ichidan. For example, 起く (oku) → 起きる (okiru, ichidan), but 過ぐ (sugu) → 過ぎる (sugiru, ichidan) or 過ぐ (sugu) → 過ぐ (sugu, godan in some dialects).
古典の「食ぶ」は現代語で「食べる」になった。
The classical 'tabu' became 'taberu' in modern Japanese.
Provide examples of nidan verb conjugations in context
Nidan verbs appear frequently in classical works like the Man'yōshū, Genji Monogatari, and Heike Monogatari. Recognizing their conjugations is essential for reading these texts.
「春過ぎて夏来たるらし白妙の衣干したり天の香具山」 (万葉集) - 「過ぐ」は上二段動詞。
'Spring has passed, and summer seems to have come; white robes are drying on heavenly Mount Kagu' (Man'yōshū) - 'sugu' is a kami-nidan verb.
Nidan verbs have distinct classical forms that differ from modern ichidan verbs. For example, the classical rentaikei (attributive form) of 起く is 起くる (okuru), not 起きる (okiru). Modern learners often mistakenly apply modern rules to classical texts.
古典では「起くる」が連体形だが、現代語では「起きる」が終止形かつ連体形。
In classical Japanese, 'okuru' is the rentaikei, but in modern Japanese, 'okiru' is both shūshikei and rentaikei.