This paper surveys the Tsuken island dialect of Okinawa Prefecture, Japan. This paper researches the case particles [ni], [Nka], and [ʃi] which are equivalent to the Japanese case particle [ni]. The following five points are elucidated: 1) The three case particles [ni], [Nka], and [ʃi] are distinguished in usage. 2) When used with a verb with the character of "movement", all three particles are used. [ni] is used when the entity is a person. [Nka] is used when the entity is non-human. [ʃi] is used when emphasising directionality. [Nka] and [ʃi] both have ties to the locative case. 3) Tsuken dialect [ni], [Nka], and [ʃi] stand in the same relationship with [tu] as Standard Japanese [ni] does with [to]. 4) In the function of marking an entity, [ni], [Nka], and [ʃi] have the function of marking the aim of or partner in an action, and form a one-sided relationship with the target. On the other hand, [tu] has the function of marking the partner in joint work and those who operate together. 5) In the function of expressing result, a null-particle, [Nka], and [ʃi] have the function of marking the result of a unidirectional change or an essential change. On the other hand, [tu] has the function of marking the result of bidirectional or mechanical change.