Thank you for submitting your item for appraisal. This appears to be a japanese short sword or Tantō 短刀, a japanese sword that was worn by the samurai class of feudal Japan. The Tantō in your possession is most likely double edged, a so called moroha type blade, the term Moroha-zukuri 両刃造り whould apply. The most important part - the incised signature - is hidden by the handle, which can easily be disassembled. Have a look at online tutorials or ask someone who has done it previously without cutting himself or herself. The estimate is based on similar sold or offered at auction.