These are Katayaki, hard <a href="https://en.wikipedia.org/wiki/en:senbei" class="extiw" title="w:en:senbei">senbei</a> for <a href="https://en.wikipedia.org/wiki/en:Ninja" class="extiw" title="w:en:Ninja">ninja</a>. These are made by Kamata Confectionery in Iga, Mie, Japan.
<a href="//commons.wikimedia.org/wiki/User:Miyuki_Meinaka" title="User:Miyuki Meinaka">Miyuki Meinaka</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>