Noh is a Japanese art form that utilizes masks. There were originally around 60 types of masks, but now there are over 200 varieties used. Masks are carefully chosen by performers depending on the specific Noh play. Masks began as religious icons but took on more human characteristics during the Muromachi period from 1392-1573 CE. Performers are able to express a variety of emotions by subtly tilting the mask up or down. Masks are valuable heirlooms passed down through generations and performers seek to "become" the mask during a performance in order to express the character's feelings.

1. All about Noh

4. A Noh is an art form that utilizes masks, there is a great variety
of them. There were originally about 60 basic types of noh
masks, but today there are well over 200 different kinds in use.
Covering the face with a mask is much like wearing makeup.
However, noh performers feel that the noh mask has a certain
power inherent in it which makes it much more spiritual than a
prop used to change ones appearance.
Taking into account the status of a certain noh, the noh
performer will carefully choose a noh mask, known also as a
noh-men or omote. In most cases, the exact mask is not
predetermined, but depending on which noh is being done, the
shite has a variety to choose from. In the end, it is up to the
shite to make the final determination as to which mask is
chosen.

5. Origin of the Noh Mask
Exactly when the noh mask came into being is not entirely
clear; however it is believed that masks, and their names still
used today, were developed from the mid to latter part of the
Muromachi period (1392-1573). Previous to that time, the
mask conventions were not entirely set and masks themselves
had stronger religious connotations. It was during the
Muromachi period that the religious significance of the masks
began to wane and they took on more human characteristics. It
is thought that as performers started to think more about the
use of yūgen (mysterious beauty) and profundity, they felt they
needed to hide the unattractive aspects of their own faces and
concentrate on making the beauty of noh stronger.

6. Noh Mask Expression: Teru and Kumoru
As it is often difficult to tell the actual feelings expressed in a
noh mask, it is said to be made with a “neutral” expression. The
mask carver tries to instill a variety of emotions in the mask.
It is up to the performer to imbue the mask with emotion. One
of the techniques used in this task is to slightly tilt the mask up
or down. With terasu (tilting upwards) the mask appears to be
slightly smiling or laughing and the expression lightens
somewhat. While kumorasu (tilting downwards), produces a
slight frown and can express sadness or crying. Basically, by
using minute movements, the performer is able to express very
fully.

7. Noh masks, like costumes and props, are extremely valuable
heirlooms and handed down from generation to generation.
After having the costume put on, the shitethen goes to the
kagami no ma (mirror room) where in front of a mirror, the
shitefaces the mask. In putting the mask on, the word kaburu
(putting on clothing) is not used. Instead the word kakeru (to
hang) or tsukeru (to attach) is used. In this way, it is implying
that the performer is “becoming” the mask, and its emotions,
in order to better express the characters feelings.

8. In reality, a noh mask does not entirely cover a noh performer’s
face when it is being worn. In fact, it is thought best if some
part of the chin and/or jowls show.
Also, as the eye holes of the mask are very small, the field of
vision of the performer is very limited when wearing the mask.
Consequently the simple design of the stage and the use of
hashira (pillars) assists in helping the performer know their
location during a performance.

10. Hitamen
Not all the main performers on stage wear masks in noh.
Usually the shite and the tsure wear masks and occasionally
there are instances where the ai will as well. The waki as a rule,
playing a character who is living in the present, does not wear a
mask. This is called hitamen or a “direct mask.”
However, even without wearing a mask, the performer is
meant to “make their face a mask.” The performer must inject
power and emotion into their performance while not using
their face to express. In some genzai noh the shite or tsure do
not wear masks.

11. Useful links:
http://www.the-noh.com/sub/jp/index.php?
mode=db&action=e_index&class_id=1
http://www.the-noh.com/en/trivia/index.html
http://www.the-noh.com/en/plays/data/program_024.html