Wikipedia
Bonkei (盆景) is Japanese for "tray landscape". A bonkei is a temporary or permanent three-dimensional depiction of a landscape in miniature, portrayed using mainly dry materials like rock, papier-mâché or cement mixtures, and sand in a shallow tray. A bonkei contains no living material, in contrast with related Japanese art forms bonsai and saikei. Its three-dimensional character and permanence distinguish bonkei from bonseki, which is a Japanese form of sand-painting that produces mostly-flat images on a display tray, usually for transient viewing before being erased for a new creation. Although bonkei materials are usually dry, flowing water and seasides are often depicted, with varying colors of gravel or sand making up the land and the water elements. A bonkei may also contain miniature figures of people, animals, buildings, bridges, and other common outdoor items.
The goal of the form is to provide an aesthetically pleasing miniature landscape for display and contemplation. The landscape is depicted in full three dimensions, and contained in a wide, low-sided tray. Raised areas representing river banks, hills, cliffs, or mountains are built up from sculptable materials like ciment fondu, clay, papier mache, or a dried and powdered peat called keto in Japan. These sculpted elements are frequently painted to resemble the natural environment as closely as possible, for example, through painting ice, rock, and vegetation colors onto sculpted mountains. Flat areas representing plains or open water are covered with colored sand or gravel. Real rocks may be embedded in the landscape.
Human and animal figurines and miniature models of structures and vehicles are placed on top of the bonkei's base landscape to create a fully realized scene. Even model trees and other vegetation may be incorporated, though live plants are not generally considered elements of bonkei. The completed bonkei can be displayed in the home similar to "a bonsai, a painting, or a floral arrangement - at proper height, against an uncluttered background".
Bonkei is similar in some ways to the Japanese saikei (plant landscape), Chinese penjing, or Vietnamese hon non bo art forms. Although the aesthetic goals and practical aspects of model railroads are quite different, some similarities with bonkei can be seen in the model railroader's depiction of the natural environment. Robert Behme says that bonkei differs from saikei in that a bonkei "is essentially a dry landscape, and living plants are rarely used; a saikei depends exclusively on living plants for effect." As a result of this key difference, many bonkei specimens can last a long time with no maintenance, where a saikei requires frequent tending and a favorable environment for growth of the trees it contains.