質問: Consider the following: に here is used in its function of denoting the time where an event occurs (に1): * ◯ 一時に1 * ◯ 一時半に1 * ◯ 月曜日に1 * ◯ 正月に1 * * 昨日に1 * ?/◯ 昨日には * * 今日に1 * ?/◯ 今日には * * 明日に1 * ?/◯ 明日には * * 去年に1 * ?/◯ 去年には * * 今年に1 * ?/◯ 今年には * * 来年に1 * ?/◯ 来年には * * 最近に1 に becomes acceptable if dative(に2): * ◯ 最近に2なって Why is it that に may not be used for the instances marked with * ? Why is には acceptable? If に1 is prohibited but には allowed, does this suggest that the に of には is distinct from に1? I think に1 may not be used to mark deictic (words which meaning depends on contextual information) nouns. I think that is what they have in common. It is not possible to have useful information about "yesterday", "today", "tomorrow" or "next year" etc. unless we have more information about the current time.
回答: Good observation that you mention deictic expressions. That is correct. Deictic pronouns with accusative case tend to be used adverbially rather than as pronouns; they already incorporate the meaning of `on` or `に`, so it would be redundant to have another ending. In traditional grammar, this is called *adverbial accusative* or *adverbial objective*. Latin clearly had an overt marking for this. As for `には`, it means a different thing. It means "by", and that will not make the expression redundant. > > * on today > > by today > > * 今日に > > 今日には > > >