The Height of a Bonsai Tree
by Carl N. Morimoto
Reprinted from  Golden Statements, Vol. XXV No. 4, July/August 2002 

If you read bonsai magazines or look at photo albums from Japanese bonsai shows, the size of bonsai are listed to give you some idea of the size. But, how are these measured? How does one measure a bonsai tree height? A measurement is significant in cases such as judged bonsai contests in Japan, where size classification may be utilized. For example the official rule for Gafu-ten, held this year (Jan, 2002) lists the shohin size requirements to be approximately 10 to 20 cm (4 to 8 inches).¹ For a larger bonsai, the precise measurements are less significant. An article in Bonsai Sekai magazine² discusses the measurements. The article’s key points are:

- Tree height is vertically measured from the tree base to the head. The head of the tree is the topmost branch tip and not the end of the needles or leaves (i.e., For deciduous trees, the head is what is displayed as its winter silhouette. For pine trees, it is not the tip of the needles but the base of the top needles, as your doctor measures your height to the top of skull and not to the tip of your hair.) As for the tree base, when the surface soil forms a high mound, it is ambiguous. It is not specified if the measurement is from the top of the mound or lower by the pot wall.

- For a tree with a top-jin, the measurement is taken from the tree base to the tip of the jin.

- For a kengai [cascade] style, where the tip of the first branch is lower than the surface soil level, the measurement is taken from the lowest branch tip to the head. In this case, the measurement is not the “tree height” but called the “top-to-bottom (vertical) distance.”

- For ishitsuki [root over rock], like the Trident maple with roots hugging a rock and reaching into the pot soil, the measurement is from the pot soil surface. However, if ishituki is a tree planted on a rock, usually the measurement is specified as “tree height with rock.”

- For hankengai [semicascade] or yoseue [group planting], often the height is supplemented with horizontal measurements.

There seems to be no precise formula for classifying bonsai into different sizes. For judged bonsai competitions, the size becomes more critical in grouping bonsai into different groups for judging purposes. Even here, the size classification may differ from show to show and year to year. Generally the accepted classification is:¹

Mame     Smaller than mini
Mini        Less than 10 cm (4 inches)
Shohin    10 cm to 20 cm (4 to 8 inches)
Kifu        21 cm to 35 cm (8 to 14 inches)
Chuhin    35 cm to 45 cm (14 to 18 inches)
Omono    Greater than 45 cm (18 inches)

References:

1.       Gafu-Tenno Gaiyou (Dai 27 Kaiban) [The Summary of Gafu-Ten Show (27^th Version)], Updated November 2001, www.shohin-bonsai.org/sub 117.htm

2.       “Explanation of Bonsai Terms – What is Head and Tree Height?” Bonsai Sekai [Bonsai World], No. 322 (March, 1997) pp.112-113.

Shohin exhibition at the Kusamura Bonsai Club Show 2006
 

“The new standard shohin size in Japan is 8 inches. This is for several reasons. Some of the new shohin stands are smaller and a 9-inch tree is just too crowded. But, more will design their newer trees and redesign those where possible to the newer 8-inch Japanese standard. The consensus of the discussion is that no tree will be frowned upon if it is not quite up to 8-inch standard, but 8 inches will be the new standard.” Golden Statements, Vol. XXVII No.4 July/August 2004,” Is Size That Important? Report from California Shohin Seminar” 2004 by Roberta Walters