The long koto is read as grace, restraint and beauty that does not need to be loud. Dream tradition links it to patience, ritual and a refined inner calm.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.