Kiko is based on Universal Laws (HoDo). Hodo is made up of two kanji. The first, Ho(u), refers to many things depending on how it is used. But in this case we mean Universal Law or Natural Law. The Do(u) is the same as any Japanese Art; do(u) refers to the Chinese Tao and tells us that this is a way, method, or path to balance our world's energies known as InYo or Shadow Sunshine.
In Shingon this idea of InYo 'Shadow Sunshine', like HoDo, also has many meanings depending on how it is used (this happens a lot when there are both (kenkyo)exoteric and (mikkyo) esoteric interpretations and practices. Also different lineages passed down different aspects, depending on what was needed and what was understood by those involved). But for kiko we are primarily talking about the interplay between opposites. In the movements we combine up down, left right, front back, in out, etc.
FuSui or wind water comes in to play, as well. FuSui deals with the flow of energy in the world and how we interact with our environment. Even we, as human beings are mostly made of air and water, we are very porous creatures. In the exoteric practice of FuSui it can be a kind of geomancy, which tells us where to place things in our homes and yards. In it's esoteric form it begins from within the very core of the 'central' individual and grows outward to include the entire cosmos.
FuSui deals with the 5 elements of Shingon (the exoteric school uses 5, the esoteric teaching has a 6th)(these include: Earth, Water, Fire, & Wind; the other two vary again according to how they are being used, but they deal with the relationship between humans, our thoughts, and Heaven / Spirit / other than man and earth stuff) that doesn't fit into an English translation (or words at all for that matter) very well. FuSui also deals with the cardinal directions, and it also works with the Sun, Moons, Stars and Planets.