The formal upright style, or chokkan, is one of the most common and classic bonsai styles. It represents a tree that grows straight and tall, with a tapering trunk and symmetrical branches. The trunk should be thicker at the base and thinner at the top, and should not bend or curve. The first branch should start at about one-fourth of the total height of the tree, and should grow in the opposite direction of the trunk. The branches should be evenly spaced and alternately arranged on both sides of the trunk, forming a triangular silhouette. The lowest branches should be the longest and thickest, while the highest branches should be the shortest and thinnest. The apex of the tree should be formed by a single branch that continues the line of the trunk. The formal upright style is suitable for deciduous trees with fine branching, such as maples, elms, beeches, and hornbeams. The style aims to create a natural and balanced impression of a mature tree that grows in an open space with plenty of sunlight.