postposition /ni/ 'on; at [time]; in'

I will go to Kyoto on Sunday.

I will go to Kyoto --> わたしは　きょうとにいきます
Sunday --> にちようび
The event described by /ik/ 'go; will go' has two roles: one the actor, and the other the goal of that movement.

Key 1: The form /ni/ describes the relation describied with the preposition /on; at; in/ in English that holds between a point in time where an event occurs and the event.
Key 2: Since every clause (or sentence) describes an event, every clause (or sentence) CAN co-occur with a /ni/ phrase describing holding an event-occurring time.
Key 3: There is no difference in the truth-conditional meanings between a clause with an order among a SUBJECT phrase, an OBJECT phrase, topic phrases, and postpositional phrases and another clause with a different order among them.

1) にちようびにわたしはきょうとにいきます。
Sunday-on I-TOP Kyoto-to go-Polite Style-Present Affirmative

The phrase にちようびに 'Sunday-on' modifies the event, and it must occur before the verb /ik/ 'go; will go'.