Which type of sights is identified as a front-blade type?

The front-blade type of sights generally refers to a simple design where a single blade is positioned at the front of the firearm, allowing the shooter to align it with the sights at the rear for aiming. In this context, fixed sights are commonly associated with a front-blade style since they do not have the ability to be adjusted for precision aiming and usually have a distinct blade shape for clear focus.

This type of sight tends to be sturdy and can be found on many traditional service pistols, including the M9. Fixed sights are often integrated as part of the firearm's design, providing a reliable aiming solution without the complications of adjustments.

The other types of sights mentioned involve features that allow for varying levels of adjustment or different aiming systems that do not fit the description of a simple, fixed front blade.