One morning, Seiji runs into Kounosuke while out on a walk. The two young men discuss recent affairs on Ryogoku bridge, but Kounosuke suddenly loses his balance and falls in the river, accidentally pulling Seiji with him and losing his precious seal box, Kogare-kou, that has been passed down in his family for generations. Kounosuke does his best to look for it, but to no avail. Meanwhile, another young man appears to have found Kogare-kou and demands a considerable sum for its return. With Kounosuke facing being disowned by his family if he cannot get the object back, Seiji and Oko do their best to help him raise the money with the help of the tsukumogami.
and so he gave it the name suou 
to distinguish it from nise-murasaki.
لذلك أعطاها اسم سوو لتمييزها 
.عن نيسي-موراساكي
also hat er sie Suou genannt,
um sie vom Nise-Murasaki abzugrenzen.
y les puso el nombre de suou
para distinguirlos de nise-murasaki.
y les puso el nombre de suou
para distinguirlos de nise-murasaki.
qu’il a inclus l’idée de « faux violet »
dans les caractères de son nom,
per questo lo ha chiamato così
 per distinguerlo da quelli nise-murasaki.
e por isso ele nomeou assim
para se distinguir do nise-murasaki.
посему было решено назвать цвет «су»,
 дабы отличать его от нисэмурасаки.