The raft bonsai style emulates the style of a tree in nature that has toppled to the ground but still survives.
The trunk of a raft style bonsai lies along or close to the ground.
The tree may be encouraged to root along the lower side of its trunk (where it sits on the ground), while the branches on the upper side of the trunk are trained to look like individual trees.
There are two substyles, ikadabuki (straight-line), and netsunagari (sinuous).
Ikadabuki (raft, straight line)
In this sub-style the trunk is entirely out of the soil. It will normally rest on the surface of the soil, but some can actually grow somewhat like a cascade-style bonsai, with the trunk slightly above the ground.
In a related sub-style, the trunk lies partially underground. This type can be difficult to maintain as the bark under the earth can start to decay from moisture and soil organisms.
Netsunagari (raft, sinuous)
The netsunagari (raft, sinuous) sub-style has highly gnarled and twisted trunk, and the roots meander through the soil like underground streams.