This obsidian stemmed tool is from Rapa Nui (Easter Island).  These tools are referred to as mata’a by the Rapa Nui people, and they were first made on the island about 400 years ago and continued to be made into the recent past.

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The mata’a in this model was struck from an angular ridge on the obsidian core.  It appears as though the stem was manufactured on the lateral edge of the flake blank, although retouching has eliminated the original platform.  The triangular shape is similar to a mata’a in the Australian Museum collection that was identified as a possible spear point through use-wear analysis.

This mata’a was acquired from Father Sebastian Englert in 1948 by the Museo Nacional de Historia Natural, Chile, where it is presently curated.

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Rapa Nui, one of the most remote islands in the Pacific, was mostly isolated during its history, from colonisation about 800 BP until the first European contact in the 1700s.  European accounts, supported later by archaeological research, documented a history of strife between clan groups on the island. One view of Rapa Nui history holds that the society collapsed into warfare due to environmental degradation prior to the arrival of Europeans, brought on by the clearing of the endemic forest of palm trees and the impacts of agriculture.  More recently, some researchers argue that Rapa Nui people were non-violent but the severe effects of European diseases and slave raids caused the fragmentation of traditional Rapa Nui society into warring factions.

Assessing the role and function of stemmed obsidian mata’a tools has been an essential aspect of research into the history of Rapa Nui.  An early view is that the widespread distribution of mata’a  across the island pointed to warfare and aggression based on the assumption that these tools were used in fighting.  Some authors claim that they could not have functioned as weapons because of their unstandardised shapes, but use-wear analysis supports a multifunctional role for mata’a, including as fighting weapons for some specimens.  Several recent use-wear and residue analyses show that mata’a were mostly used for cutting and scraping plant material, processing fish, working bone and shell, and cutting or piercing skin.

Rapa Nui oral traditions say that mata’a were used to arm two types of fighting spears: thrown spears (called kakau) and thrusting spears (called vero).  An account from 1870 states that the kakau was thrown underhand with the intent to cause a cut to the legs and arms of an adversary.  A forensic study of human skeletons identified skull fractures caused by sharp-edged implements, including two with embedded obsidian fragments probably caused by mata’a.  Mata’a for fighting were treated with magic (tohu) to make them more dangerous:  feathers were attached on either side of the spear point and the owner invoked the family spirit (aku aku) to explain to the mata’a the reason for the approaching fight.  This suggests that mata’a were considered to have agency of their own.  The mata’a was bound onto the spear shaft with string made of hau fibre, and the number of windings was different for each clan.  If the mata’a killed someone in conflict, it received the title of mataa ika, perhaps invoking the notion of human sacrifices, called ika.

Mata’a used for fighting were spiritually important to the Rapa Nui, but proportionately few of these tools were probably used as weapons.  Nevertheless, all mata’a were likely of significant cultural value, even those used for everyday tasks.  An account in 1919 by the famous anthropologist Katherine Routledge—the first researcher to make systematic observations of Rapa Nui archaeology and culture—stated that each of fourteen different mata’a shapes were given names in the Rapa Nui language.  These names translated as ‘tail of a fish’, ‘backbone of a rat’, and ‘leaf of a banana’, but not all of the names were recorded.  This degree of attention to the shape of the tools suggests that they were of deep social significance, and archaeologists have suggested that an important function of the tool may have been to signal the identity of the owner’s affiliations or status.  Stemmed mata’a are thought to be depicted in two iconic glyphs in the famous Rongorongo writing system, perhaps representing authority or violence.

Obsidian mata’a continued to be made into the recent past. An elderly flintknapper named Hé, of the Marama clan, was still making mata’a in 1919.  Examples of his work were acquired by Routledge, and these are curated in the British Museum.  Unused (and presumably recently-made) mata’a were procured by the paymaster of the ship Hyäne in 1882, and are curated in the Australian Museum.

Mata’a were made from obsidian available at three quarries on the southwestern part of the island, and a fourth on the smaller offshore islet called Motu Iti.  To make mata’a, large flakes were struck from thick blocks or slabs of obsidian.  Some mata’a blanks were then struck from the ventral surfaces of these large quarry flakes.  This method is called the ‘Kombewa technique’ by some archaeologists, named for a similar technology used to make tool blanks in Africa.  The mata’a blanks struck by the Kombewa technique have the original ventral surface of the quarry flake on one face (sometimes called a ‘detachment scar’), and the blank’s own ventral surface on the reverse face.  The technique is ideal for making a robust but razor-sharp working edge.  A remarkably similar Kombewa technique was used to make blanks for obsidian stemmed tools on New Britain, near New Guinea, but the chronological and spatial distance between these artefact assemblages argues for independent invention of the Kombewa technique on Rapa Nui.  The edge of the mata’a blank was not retouched initially, although use-wear flaking and possible retouching is sometimes seen on discarded mata’a.

Not all mata’a were made on Kombewa flakes and the considerable variation in tool shape indicates that any large- or medium-sized obsidian flake might be chosen to make a mata’a.  The stem was often manufactured on the thickest part of the flake, which was usually at the platform end.  However, the stems were sometimes made on the lateral margins of the blank, and the blank’s platform can still be clearly identified.  The stems were made by bifacial percussion flaking, as indicated by the large, deep scars.  The upper part of the stem is often within a distinctive notch, and to strike flakes from a confined part of the margin indicates that a narrow percussion tool was used for this.  Alternatively the flakes may have been struck using a narrow punch in an indirect percussion technique.

Hafted examples of mata’a knives are curated in the British Museum and the Field Museum of Natural History, showing how the Rapa Nui toolmakers integrated the stemmed obsidian tool with a handle.  On the Field Museum specimen (FM273320), acquired by the anthropologist Alfred Fuller and collected prior to ca. 1936, the wood handle is about 14 cm long and 3 cm in diameter with a recess for the stem carved onto the side at one end.  A recess for the cordage was carved on the opposite side.  The basal end and upper end of the handle were rounded off.  The stem of the obsidian tool was wrapped in bark tapa cloth and placed onto the recess with a tapered small wood wedge-peg placed on top of the tapa cloth along one side of the stem.  The stem and wedge-peg was then bound to the handle with fine fibre cordage.  The tapa cloth created a non-slip surface for the cordage and protected it from the sharp edge of the stem.  Driving the tapered wedge-peg upwards under the secured cordage presumably provided added tension to the binding.  The mata’a was made on a Kombewa flake and hafted with the curved, unretouched edge at right angles to the handle.  The platform struck to create the mata’a blank is on one side of the tool, with the stem flaked onto the blank’s lateral edge.  The hafted mata’a knife in the British Museum (Oc,EP.17), illustrated by Routledge in 1919 but collected in the 1830s by the famous botanist Hugh Cuming, also appears to be made on a Kombewa flake, and is remarkably similar in size, shape, and workmanship to the Field Museum specimen made some 100 years later.  The tapa cloth appears thicker on this tool, and two wedge-pegs were used, one on each side of the stem.  A second hafted mata’a in the British Museum (Oc,EP.18), also collected by Cuming, has a much longer handle (ca. 21 cm), no recess for the stem, no wedge-peg, and is less-carefully bound onto the handle.  The haphazard way the tool is hafted may indicate it was made for exchange with European sailors rather than for use.  It too appears to be made on a Kombewa flake.