on that occasion; at that time; in that case
Refers back to a previously mentioned situation or event, often used in formal or written contexts to mean 'when that happens' or 'in doing so'.
The meeting date has been set. On that occasion, we will send you detailed materials.
If you change your password, you will need to log in again at that time.
Archaic kanji form using 其の for その; rarely used in modern writing.
Compound of その (that) and 際 (occasion, time).