"Indeed, at the rituals of the installation, the chief is invested with the 'rule' or 'authority' (lewaa) over the land, but the land itself is not conveyed to him. The soil (qele) is specifically identified with the indigenous 'owners' (i taukei), a bond that cannot be abrogated. Hence the widespread assertion that traditionally (or before the Lands Commission) the chiefly clan was landless, except for what it had received in provisional title from the native owners, i.e., as marriage portion from the original people or by bequest as their sister's son ...

The ruling chief has no corner on the means of production. Accordingly, he cannot compel his native subjects to servile tasks, such as providing or cooking his daily food, which are obligations rather of his own household, his own line, or of conquered people (nona tamata ga, qali kaisi sara).

Yet even more dramatic conditions are imposed on the sovereignity at the time of the ruler's accession. Hocart observes that the Fijian chief is ritually reborn on this occasion; that is, as a domestic god. If so, someone must have killed him as a dangerous outsider. He is indeed killed by the indigenous people at the very moment of his consecration, by the offering of kava that conveys the land to his authority (lewaa). Grown from the leprous body of a sacrificed child of the native people, the kava the chief drinks poisons him."

"Sacred product of the people's agriculture, the installation kava is brought forth in Lau by a representative of the native owners (mataqali Taqalevu), who proceeds to separate the main root in no ordinary way but by the violent thrusts of a sharp implement (probably, in the old time, a spear). Thus killed, the root (child of the land) is then passed to young men (warriors) of royal descent who, under the direction of a priest of the land, prepare and serve the ruler's cup ...

...the tuu yaqona or cupbearer on this occasion should be a vasu i taukei e loma ni koro, 'sister´s son of the native owners in the center of the village'... Traditionally, remark, the kava root was chewed to make the infusion: The sacrificed child of the people is cannibalized by the young chiefs.

The water of the kava, however, has a different symbolic provenance. The classic Cakaudrove kava chant, performed at the Lau installation rites, refers to it as sacred rain water from the heavens... This male and chiefly water (semen) in the womb of a kava bowl whose feet are called 'breasts' (sucu),

(pictures from Lindqvist showing very old Chinese cooking vessels)

and from the front of which, tied to the upper part of an inverted triangle, a sacred cord stretches out toward the chief ...

The cord is decorated with small white cowries, not only a sign of chieftainship but by name, buli leka, a continuation of the metaphor of birth - buli, 'to form', refers in Fijian procreation theory to the conceptual acception of the male in the body of the woman. The sacrificed child of the people will thus give birth to the chief.

But only after the chief, ferocious outside cannibal who consumes the cannibalized victim, has himself been sacrificed by it. For when the ruler drinks the sacred offering, he is in the state of intoxication Fijians call 'dead from' (mateni) or 'dead from kava' (mate ni yaqona), to recover from which is explicitly 'to live' (bula). This accounts for the second cup the chief is alone accorded, the cup of fresh water. The god is immediately revived, brought again to life - in a transformed state."

"There is a further motivation of the same in the kava taken immediately after the chief's by the herald, a representative of the land. This drinking is 'to kick', rabeta, the chief's kava. Raberabe, the same reduplicated version, means 'a sickness', the result of kicking accidently against a 'drau-ni-kau'... The herald here takes the effects on himself: drau-ni-kau is the common name for 'sorcery'..." (Islands of History)

On Easter Island they had not the kava root. Instead they used the word kava for ginger (gingembre, according to Bishop Jaussen's word-list, ref.: Barthel). And ginger roots are yellow, twisted and knobby:

Picture from Internet (Wikipedia). It is said that the root of Zingiber - from Tamil Iñci Officinale - traditionally was eaten by pregnant Chinese women to 'combat morning sickness'. In India they apply it to the temples (i.e. to the sides of the head) as a paste to relieve headache. Both these uses harmonize with what has been proposed above.