Koukan (a Touhou LW original) refers to a corona, an optical phenomenon where a circle of light surrounds the sun or moon due to diffraction. An apt temperament for Keine, who records history according to the cycles of the sun and moon. Keine is endowed with Earth Phase, with her acceptance and creation of history, and Sun Essence, as she strictly adheres to rules. The encompassing and regenerative Earth Phase resists Fire Phase, because fire produces earth, but it is weak to Wood Phase, because wood parts earth. The alluring and arrogant Sun Essence resists the diverse and uncooperative Star Essence, but it is weak to the cooperative and indecisive Moon Essence.

Editing history is Keine Kamishirasawa's ability as a were-hakutaku. In her human form, she is capable of "eating" history, whereas in her hakutaku form, she is capable of "creating" history. This ability is most likely derived from how Chinese mythology portrays the hakutaku as an auspicious beast that appears before monarchs. Perhaps a monarch's power to edit the history books is reflected in this ability that instantly alters history with magic. Records and accounts transcribed into history books that stand the test of time are readily accepted as truth, regardless of their accuracy. Conversely, history books that may actually be true but do not withstand the test of time by either being burnt or expunged in some other manner are thus forgotten and no longer recognized as history. The people of subsequent generations have no other means of knowing what happened in the past, except through the history books that are still available to them, leaving them utterly oblivious to any records that have been erased. This is how the truth is edited. It appears that Keine uses her ability solely for humans. She carefully edits history in order to prevent the occurrence of needless conflicts and disputes. Also, since she only takes the form of a hakutaku when the moon is full, she does all her history editing on this single night each month. (She probably doesn't get much sleep.) While editing history, Keine can recall the truths that she once ate (hid) in her human form, and can edit them back into history if she so wishes. It is assumed that when Keine eats history, those who knew the details that were eaten by Keine pertaining to that particular moment in history forget those details. However, someone older who knew the same details from an earlier moment in history retains that knowledge. It may be possible for Keine to alter the memories and perceptions of specific people by eating different parts of history, which makes this ability an effective tool for protecting humans from youkai.