noun, noun which may take the genitive case particle 'no'
past days; bygone days; days of yore
Literary expression for a time that has passed, often with a nostalgic or poetic tone. Used as a noun or with の to modify another noun.
Memories of bygone days come back to me.
I recall how he looked in days gone by.
noun which may take the genitive case particle 'no', noun
while still alive; during one's lifetime
Refers to the time when someone was alive; often used in reminiscence about a deceased person. Can be used as a noun or with の.
My grandfather, in his lifetime, often took walks in this park.
My mother's words from when she was alive still remain in my heart.
I can't forget my father as he was when he was alive.
Friends gathered to reminisce about the days he had lived.
The old photograph still holds traces of how things once were.
生前 is a neutral, often legal or biographical term for 'during one's lifetime', while 在りし日 has a poetic, elegiac tone when speaking of the deceased.
往時 is a formal literary term for 'bygone times' used in writing about history or eras, whereas 在りし日 usually evokes personal or emotional memories.
Standard kanji spelling; the literary auxiliary verb し (past) attaches to 在り (archaic ラ変 verb 在り).
Kana-mixed spelling; common in modern writing when the kanji 在 is omitted.
From the archaic verb 在り (ari, 'to be, to exist') + the classical past auxiliary verb し (shi) + 日 (hi, 'day'). The phrase literally means 'the days that were' and is used in modern Japanese as a set literary expression.