This In Brief is part of a miniseries on Oceanic diplomacy introduced in In Brief 2021 / 23. This paper looks at the longstanding and effective diplomatic system that has existed between Guadalcanal tribes, clans and individuals that we might call the popo and supu system. At its core are food exchanges, feasting and presentation of valuables through crafted popo (a wooden bowl filled and decorated with cooked food) or supu (a heap of uncooked food and live pigs) with reciprocal protocols that maintain friendly relations, solve disputes and strengthen or create new allies. While the popo and supu system continues to play a significant role in managing relations between people across Guadalcanal, the Solomon Islands state has also adopted elements of the system in its efforts to resolve conflicts within the state as well as in its external diplomatic rituals.