The length of a Shirasaya sword can vary depending on the specific sword and its intended purpose. Shirasaya is a traditional Japanese sword mounting style characterized by a plain wooden scabbard (saya) and handle (tsuka) without decorative fittings.

In general, the blade length of a Shirasaya sword typically follows the standard length range for Japanese swords. A typical katana blade, for example, is around 2 to 3 feet (60 to 90 centimeters) in length. However, the length of a Shirasaya sword can vary, and it is not uncommon to find longer or shorter blades.

Shirasaya swords are often used for storage or as a minimalist style for preserving and displaying a sword. They are not typically used for active combat or cutting practice. As a result, the focus is more on the preservation and presentation of the blade rather than specific functional specifications.

It's worth noting that Shirasaya is a style of mounting, and the length of the blade can vary depending on the swordsmith's design or historical context. If you are referring to a specific Shirasaya sword, it would be best to consult the individual sword or its documentation for the exact measurements.