|Used in||Higurashi no Naku Koro ni Chikai|
|Release Date||April 8, 2009|
|Number of Tracks||4|
Chikai (誓い, Vow) is Eiko Shimamiya's fourth single produced by I've Sound and Geneon Entertainment label. It is set to be released on April 8, 2009, a year after releasing her third single Wheel of Fortune. The title track is used as the opening theme for Higurashi no Naku Koro ni Chikai (ひぐらしのなく頃に誓), the live-action film sequel for the first Higurashi no Naku Koro ni live-action film.