The practice of bonsai classifies trees into categories based on factors such as height and ease of handling the tree. Some classes of bonsai require extra attention and maintenance, while other sizes offer easier care for beginners and experienced practitioners alike.

If you own bonsai, do you happen to know the size category of each tree? If you’re a bit perplexed at the question, then get ready to learn about an aspect of bonsai practice that receives relatively little attention – the bonsai size classification system. 

Bonsai Size System Basics

The custom of assigning a size category to bonsai evolved for use in competitions and exhibitions. Bonsai trees fall into specific named categories according to their heights. According to this system, bonsai can range from a minuscule 1″ in height to a whopping 80″ tall. Height is generally measured from the rim of the pot to the top of the tree.

Interestingly, the system is somewhat subjective. Some categories go by more than one name, and some exhibitions redefine the classes based on their own rules.

Figuring out the appropriate category for an individual tree isn’t always straightforward. Height ranges for a number of categories overlap, so a particular tree might actually qualify for inclusion in two – or even three – categories! 

Furthermore, another traditional type of classification – the “hand” system – is usually referenced along with the named categories. The “hand” system harkens back to ancient times. It relates the size of the tree to the number of human hands needed to move it. For example, a “one-hand” bonsai is small enough to be moved with a single hand, while a “four-hand” specimen would need two people to handle the tree in its pot. The largest bonsai, “eight-hand” trees, require the efforts of four people.

Whether or not a bonsai practitioner has interest in entering competitions, its useful to be aware of the bonsai size classification system. Let’s take a look at this aspect of the hobby, break down the various categories from within the major size groupings, and see where your trees fit.

Miniature Bonsai

There are two categories of truly tiny bonsai, so small that they do not even qualify as one-handed trees. They reside in miniscule pots, often shaped like thimbles.

The Keshitsubo category is the smallest class of bonsai, measuring only 1’ to 3” (3 to 8 cm) in height. Known as “poppyseed” bonsai, they are essentially artful-looking seedlings which have received little to no training or design. These bonsai can be easily lifted with only two fingertips. 

The only slightly larger Shito bonsai category measures 2” to 4” (5 to 10 cm). This size class is commonly called “fingertip bonsai” because they can be lifted with just the tips of a person’s fingers. 

Because they are so small, these miniature bonsai tend to have very little detail and minimal foliage. Therefore, instead of resembling full-grown trees in miniature, these tiny trees depict more of a suggested or idealized version. 

Although miniature bonsai are undeniably cute, cultivating them presents a number of challenges. One obstacle is that the tiny pots needed for these size categories can be more difficult to find than pots designed for larger bonsai.

When it comes to the little trees themselves, they require vigilant monitoring, because the soil in their tiny pots dries out very quickly. In hot weather, this might require multiple waterings over the course of a day, as well as special treatment such as placing the pot in a tray of water. Unfortunately, trees in these miniature categories tend to be short-lived.

Small Bonsai

The next three categories constitute the class of small bonsai. The majority of bonsai enthusiasts who enjoy the challenge of working with smaller trees cultivate specimens that fall within these size ranges. 

Mame bonsai measure 2” to 6” in height (5 to15 cm). Also referred to as “palm size”, they earn the “one-hand” classification.

The next size up, the Shohin category, is a popular size range for many practitioners. Also sometimes referred to as Chohin, it encompasses trees 5” to 8” (13 to 20 cm) in height. 

The Kumono category expands the realm of small bonsai a bit further. These “one-hand” trees measure 6’ to 10” (15 to 25 cm). 

The “one-hand” categories, with their corresponding small pots are slightly less demanding than the miniature trees, but they do require additional and more careful care than most larger bonsai. They must be checked and watered frequently during hot weather. While these bonsai have more foliage – and therefore more capacity for achieving the look of mature trees – pruning must be frequent and well-planned in order to achieve the tree’s full potential.

Interestingly, anyone who owns a 6” tall bonsai might be surprised to note that a tree this size qualifies for inclusion in all three of the small bonsai categories. For practical purposes, the bonsai owner could make the call. 

Participation in an exhibition or competition is the only time a bonsai’s size classification actually matters. In that case, the rules of the individual show determine the category assigned to the tree. For example, some shows expand the Shohin class to include Kumono trees, categorizing bonsai up to 10” high as Shohin.   

Medium Bonsai

The most popular sizes for bonsai trees fall towards the middle of the continuum, and medium-sized trees exemplify the quintessential bonsai. In the medium categories, height ranges start to expand and practitioners experience easier tree care and wider options for styling.

Katade-mochi is one of the most common sizes of bonsai, measuring 10” to 18” (25 to 46 cm). Although the category is considered “two-hand”, the smaller end of the Katade-mochi size range can still qualify as “one-hand” trees. Small enough to handle, yet big enough to effectively shape and prune, the Katade-mochi size represents a sweet spot in size for bonsai practitioners.

Chiu or Chumono bonsai vary from 16” to 36” (41 to 91 cm) in height. The collections of many experienced bonsai practitioners contain this size of “two-hand” bonsai.

Large Bonsai

Large bonsai exist largely within the realm of museum and arboretum holdings. However, many experienced hobbyists also work with the larger tree sizes. 

Dai or Omono are sizeable trees that qualify as “four-hand” bonsai. They range in size from 30” to 48” (76 to 122 cm).

The next size category, Hachi-uye, encompasses trees measuring 40” to 60” (102 to 152 cm) in height. These very large trees are regarded as “six-hand” specimens, due to their size and weight.

The zenith of bonsai sizes is the Imperial category. This category takes its name from the Japanese imperial gardens, where many bonsai of this size reside. With a range of 60” to 80” (152 to 203 cm), these eight-hand trees are the height of a medium to very tall person.

These large bonsai present their own set of challenges. Moving or repotting any of these larger size trees requires multiple helpers. The large pots are very expensive and can be hard to find. It may also be challenging to obtain wire thick enough to effectively shape branches.

As one might expect, large bonsai are usually old and extremely valuable. This makes keeping them healthy with close attention to proper care of utmost importance. That, coupled with the sheer size of the trees, means that the majority of these large bonsai live in institutional settings with personnel dedicated to their daily care.  Read our article to learn about venues exhibiting larger bonsai.

Which Bonsai Size is Best?

Beginners may be wondering which size of bonsai they should be looking to collect first. As we’ve covered earlier, the smallest and largest categories present special challenges, and therefore are not the best places to start.

We recommend that beginners look first to acquire trees that fall in the Kumuno (6” to 10”) and the Katade-mochi (10” to 18”) categories. These categories span the small-to-medium classes and qualify in several respects as good starter bonsai. Trees are readily available as nursery stock, pre bonsai and bonsai. Pots that fit them are also easy to find. Another plus – the cost of acquiring both stock and pots is fairly economical at these sizes. Explore our articles on selecting nursery stock, choosing pre-bonsai and picking a pot to learn more about these subjects.

After successfully managing trees in this size range for a few seasons, the more experienced beginner might opt to experiment with larger-sized trees by buying bigger stock or trying field collecting. Alternatively, the enthusiast might prefer to go smaller by working with mame or shohin bonsai. Either way, the experience gained with the mid-sized trees will provide a helpful stepping stone for success with the more challenging sizes of bonsai.

In this article, we explored the breadth of the size classification system used in the practice of bonsai. We also looked at special considerations for cultivating some classes and covered which work best for beginners. From the tiny, thimble-sized Keshitsubo and Shito bonsai categories to the massive Imperial class of trees, there is a bonsai size perfectly suited for every enthusiast.