Mempo

Hoate (Cheek 頬当)) are menpo (face armor) without a nose. Specifically made to cover the face below the eyes to below the chin and includes the tare (throat guard).  The hoate were commonly refereed by samurai warriors as a battle mask and was the Men-yoroi (facial armor) of choice by many samurai on the battlefield. It provided  jaw and chin protection without impeding vision or breathing.  

The menpo was traditionally used, not only to protect the face in battle, but to help hold the shinobi-no o (kabuto cords) in place. Holding the cords in place, prevents chafing, and keeps the kabuto (helmet) tied securely to the warrior’s head.  The shinobi–no-o, typically tie around the ore kugi (L-shaped post), located on the menpo cheeks, and then down under the chin.