Trough zithers are a group of African stringed instruments, or chordophones, that look like wooden bowls, pans, platters, or shallow gutters with strings stretched across the opening. These instruments are a type of zither and can produce quiet sounds, depending on how they are shaped. The sound is often made louder by adding a gourd resonator. There are five different types of these instruments, classified based on their shapes.

The resonator is most often a gourd, but sometimes tin cans are used instead.

Trough zithers are an instrument found mainly in East and Central Africa, especially in Rwanda and Burundi. They are also found in parts of the Democratic Republic of Congo and Tanzania, near the borders with Rwanda and Burundi.

Types

Ulrich Wegner (1984) groups East African shell zithers into five categories based on their shapes.

• Type A: A six-string zither tied to a calabash. Used by the Shi language group near Bukavu in eastern Congo. Found in the Royal Museum for Central Africa.
• Type B: A six-string bowl zither called ligombo, used by the Nyamwezi in Central Tanzania. It lacks a gourd resonator.
• Type C: An unnamed trough zither with no known name, found in Rwanda.
• Type D: A trough zither called nanga or possibly kinanda, used by the Acholi people in South Sudan or Northern Uganda. Also includes an arched harp and an unnamed flute from around 1880.
• Type E: An unnamed trough zither found in the Democratic Republic of Congo in the late 19th century. Measures 13 x 6 inches (33 x 15.2 cm).

The inanga, a wide, flat bowl-shaped zither with low edges, is part of Type A. A single string runs continuously around notches on the narrow, rounded sides.

The ligombo of Type B has a narrow, flat shape that tapers toward the middle. Strings pass through holes on the narrow sides. It is used by the Wakinga in southern Tanzania, the Sangu in the Mbeya Region, the Bena in the Iringa Region, and the Kaguru in central Tanzania, in addition to the Hehe people.

A shorter version of the ligombo with seven strings, called sumbi, is used by the Safwa people living in the area of the Sangu in the Mbeya Region.

Type C differs from Type B by having a deeper, semi-tubular shape and straight walls. It is found north of Type B’s area, used by the Gogo in Dodoma, the Turu in Singida, the Sandawe in Kondoa, and the Isanzu in Iramba.

Type D is long and narrow, with a flat bottom and straight walls. It is found along the east coast with the Zaramo and Kwere in Pwani, and further south with the Makonde.

In eastern central Tanzania, the Makonde and Nguru (Ngulu) people use a wide, rectangular bowl-shaped zither with a flat bottom, which is also part of Type E.

Playing

The musician uses both hands to play the inanga. The instrument is placed in the player's lap or on the left side. The left little finger holds the top of the instrument, and the other fingers of the same hand pluck the topmost strings. The right hand plucks the bottom strings, which produce the lowest notes.

Inanga Burundi of Burundi uses a different method. He places the instrument on his lap, facing away from him. He plucks the bottom strings with one hand from the side and reaches over from above with the other hand to play the top strings, using his forearm to support the instrument.

The instrument has also been seen lying flat on a table. The player reaches across from the top with both hands to pluck the strings.

The inanga is not used to play chords. Instead, a rhythmic and melodic pattern is played and repeated. Singing often happens while the instrument is being played. The instrument is tuned before playing, but notes can be changed during playing by pressing down on the end of a string while plucking with the other hand.

Each tribe has traditions about who may play the instrument. For example, among the Kunta and Ziba tribes, men played the instrument. In the Hima tribe, women played it. Among the Kiba, men were the main musicians, but women also played the instrument.

A picture by Ulrich Wegner shows the Ligombo being played. The musician holds the instrument so it faces him, plucking the strings with his thumbs. The instrument’s resonating gourd can also be used as a rhythm instrument. Wegner noted that the second person in the photo was "accompanying him rhythmically on the resonator" with his bare hands.

One way the Acholi play the instrument is as a fast rhythmic tool. The musician sits on the ground and plucks the strings with their thumbs, creating a repetitive melodic beat for dancers.

Characteristics

The body or bowl of the instrument can be a shallow platter, like the Inanga, or large and deep enough to hold a baby. These instruments are typically made from a single piece of wood with slots at each end. The overall shape may be round and tube-like or shaped like a rectangle.

Historically, strings were made from natural materials, such as plant fibers or "cow sinew." A long piece of string is threaded through holes or notches, moving back and forth from one end to the other, forming separate string segments.

The ends of the string are often wrapped around wooden pegs to keep them in place. The string is adjusted by tightening or loosening it. This process affects multiple string segments because changing one part influences the others.

The "sharp, sawtooth notches" help control the string's tension by gripping it tightly. A wooden stick can also be used to adjust tension by placing it under the strings at each end.

Some instruments use holes instead of carved notches.

Gourds are sometimes attached to the bottom of an instrument by threading them through holes on the sides or bottom of the instrument into holes in the gourd. The gourd acts as a resonator, helping to make the sound louder. The bottom of the bowl may also have soundholes. Over time, the wood of the instrument may crack as it dries. These cracks are often repaired by joining the two halves with tin and nails or by wrapping the instrument with cord and tightening the halves together.

Distribution

Trough zithers are an African invention. In East Africa, they are found in many places, including Tanzania and the area between Lake Victoria, Lake Kivu, and Lake Tanganyika. They are also found in Uganda, Rwanda, Burundi, and eastern Congo.

List of historical trough zithers

This list tries to connect the names of known trough zithers with people or places linked to those instruments. Sometimes, the information is not as detailed as in the original sources. For example, a source might mention a specific group in a certain area, but this list separates the group from the location. An example is the Hutu people of Rwanda, who are listed as playing the inanga. It is possible that not all Hutu groups play the inanga, and not all groups in Rwanda use the instrument.

Another point is the names of the instruments. These names were written down by people who found or bought the instruments. This might lead to errors in accuracy. Also, even if the names were recorded correctly, they might not always mean the same thing. For example, a name could refer to a specific instrument, all string instruments, or instruments in general. Different groups might use the same name for different instruments. For example, the name "Ngombi" could refer to a Zande trough zither, a harp used by some groups, a lamellaphone used by others, or a slit drum used by another group.

Traditions change over time. The information here comes from museum collections and books written in the 20th century.