Thank you for submitting your item for appraisal. This appears to a japanese Mon or Kamon, used to identify an individual or a group, similar to a western coat of arms. Such flags are sometimes used during religious Festivals, each participating group flying their particular flag. There are thousands of Mon currently in use in Japan. The one in your possession is constructed of several japanese characters intertwined. Due to the artistic freedom involved, this is very hard to decipher. Even if it would be identifiable, this would not increase the value very much. The estimate is based on similar flags offered or sold at auction.