Crispin Howarth notes, "Very little has been recorded regarding the brightly painted bulbous masks of the Yuat River. While their use by the Biwat people is not clear, these masks are known to have been traded and incorporated into ceremonies and performances by other communities on the Sepik River itself, particularly in association with initiation rites.
All are pierced through the eyes with the intent to be worn over the face and some examples [as in the present work] still retain their decorations and the cane and fiber section that secured the work to the wearer's head. . . .
These masks are quite likely to represent both bush spirits (maindjimi) or water spirits (saki) when used by the Biwat people. Like masks elsewhere along the Sepik River, each depicted a particular spirit and had a personal name." (Myth and Magic - Art of the Sepik River, Papua New Guinea, National Gallery of Australia, 2015, p. 111)
Mostly known for their exquisite flute stoppers, the Biwat artists carved a variety of masks, yet they mostly share the same characteristics of the work presented here: overall bulbous design in oval form with rounded pierced nose, pursed projecting lips with open mouth and great emphasis on the eyes. In the present work, the eyes are accented by circular incisions inlaid with ochre paint and then each are extended in a hallucinogenic amoebic-form design curving downward and then up to a point behind each ear and highlighted in white pigment. A beard of human hair is attached to the cane and fiber section along the bottom.
Cf. New Guinea Art - Masterpieces from the Jolika Collection of Marcia and John Friede, Fine Arts Museum of San Francisco, 2005, fig. 142 for a mask now in the National Gallery of Australia, and fig. 140 for a ceremonial house finial figure with a strikingly similar face.