What Is the Best Wood for a Jo Martial Arts Weapon?
The following is the first chapter of a book in process, titled "Bokken, Jo, and Related Wooden Weapons." Other chapters cover the blueprint of diverse weapons used in Aikido training including observations on wooden swords and their schools of origin.
Introduction
The qualities that define the grapheme of Bokken, Jo and other traditional Japanese wooden weapons, rest entirely on the integrity of the textile itself. There are hundeds of forest choices overall and many regional varieties worthy of consideration only every bit we shall see in this section at that place are actually very few that are well suited for all situations that martial artists run across in their weapons preparation.
The Japanese have always used their native evergreen white oak (Shiro Kashi) for nearly preparation weapons used in paired practice where there is likelyhood of bear upon with a partner'due south wooden weapons or armor. Kashi isn't generally considered a "fine" woods but its tough, reliable, relatively dense character is well suited for touch on tool handles and martial art equipment. Many other materials and forest species are available in Japan. Unique weapons of unusual construction and materials, including several superb tropical varieties, are produced but but intended for settings advisable to their scarcity, toll and appearance. Centuries of practical wisdom support this stardom between the utilitarian and the formal equally it relates to martial fine art weapons.
The extension of the Japanese martial arts to other parts of the earth, where no native tradition exists in the manufacture of related practice equipment, fosters attempts to produce traditional wooden swords and the similar without the do good of any accumulated local wisdom or reliable material from local sources. Because of this, there has been a tendency of non Japanese to overlook a distinction which is taken for granted in Japan - the role of materials suitable for routine practice and that of materials which are appropriate for presentation and ritual. Instead, many foreign practitioners view all equipment on a purely "qualitative level" and perceive the value of one's practice as being influenced by the degree of dazzler and precision of the weapon - a notion by and large discouraged by both Japanese and non Japanese masters and one, I think, that remains an obstruction in the development of weapons training. The following department is intended to guide the reader to an understanding of diverse materials and their advisable use.
For both the utilitarian and refined, the woods is the weapon. Its strength, density, stability, color and texture are the potential for quality. Although a mediocre weapon may come from an exceptional slice of wood, information technology will always take within it the possibilities dictated by the the quality of the material. No corporeality of artistry will make a skilful do weapon out of a mediocre piece of wood.
As information technology turns out, there are very few kinds of woods that are suitable for wooden weapons, especially ones longer than two feet or then where density and shock stength are important. Virtually hardwoods, peculiarly the dozens of commercial species including native oak, maple, cherry-red, walnut etc. have mechanical drawbacks and most modern synthetic materials are not esthetically or historically appropriate to the traditional martial arts. It is little surprise that the materials chosen in this situation are not often seen in common woodworking where and so many other readily available options exist.
The descriptions and information hither include factual data apropos wood selections based on the production of thousands of wooden weapons for Japanese martial arts, published information and actual tests of hundreds of wood samples subjected to the stresses expected in paired practice.
Information technology is necessary to categorize information and the following written report, like all others, combines individuals of a species as if they were ane but actually reflects an boilerplate of many unique members. In the instance of natural woods in that location are meaning differences within a species and the reader should consider the diverseness: For example, American Black Walnut in full general doesn't take suitable shock strength or dent resistance for this application and we would exist tempted to unequevically extend this judgement to all Black Walnut. Nether some (rare) atmospheric condition however, an individual tree may produce lumber that will produce a servicable and possibly an splendid do weapon. Several of the true hickories from a specific region (which will be discussed later) yield excellent quality lumber in general but an individual slice may be weaker than unusually good piece of material from an "inferior" species.
Impact Strength
Whereas the quality of wood tin can be described from many perspectives, one of the principal concerns here is its safety and strength during contact which typically occurs with sudden touch on. The following nautical chart, Affect Strength of Materials, shows the strength of diverse materials when subjected to impact shock (with other wood) expected during paired practise. The test uses a simple leap loaded ram* to examination samples of identical size. The sole purpose of the exam is to decide if a item material has potential every bit a martial fine art weapon but some woods species are included to provide comparative data even if they would not qualify for other reasons.
(For those interested in the physics of the test: The strengh of natural woods (used as structural members) is well documented in published data where samples are subjecting to slowly applied loads. This test all the same is specifically designed to test shock forcefulness as it relates to martial art exercise. A hardwood ram, attached to a fiberglass jump, impacts equal sized test samples on the tangential surface. The leap'south deformation is proportional to the magnitude of the practical force. The bear on energy is calculated according to the relationship Eastward=1/2ky2. Impact free energy tin can be represented as the square of the calibrated distance that the bound is deformed. Samples are subjected to gradually increasing impacts until failure. The numerical values on the nautical chart correspond the touch on energy that broke the sample. Virtually values are the boilerplate of five or more samples of the same species. )
White pine is included for reference. American White and Ruby Oak, both ring porous hardwoods, might have sufficient strength just their open grain presents exposure to damage in those areas.
In many cases, very difficult and heavy hardwoods such every bit African Ebony show to exist relatively breakable. Other exotic species such as Greenheart,Blackheart, Blackwood, Leadwood etc all tend to have excellent resistance to denting but low daze strengh. These materials would evidence little harm at lower impacts but might break unexpectedly with a college affect. Lignum Vitae, a woods with extraordinary properties, invariably develops checking (either superficial or more astringent groovy) due to atmospheric humidity swings and its utilise a martial art weapon would not bear witness to be a wise utilise of resources.
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and included footnotes
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Density
Along with bear on force, forest density is a key consderation in weapon quality. Information technology is unremarkably measured as a ratio called specific gravity. When wood floats in water, its specific gravity is less than i but at that place are a few varieties, mostly of tropical origin, that have specific gravities greater than ane and will sink. Loftier density does not necessarily translate into loftier touch on strength. There are several dense woods that have a much lower bear upon strength than other less dense ones as shown below. Please review the information in the above chart "Impact Strength of Materials" and included footnotes which describe the impact test and clarify the information in the following table.
| Woods | Specific Gravity | Impact Strength | |
| White Pine | .35 | 86 | |
| African Ebony | 1.ten | 110 | |
| Cerise Oak | .63 | 169 | |
| Purpleheart | .79 | 173 | |
| Pau Ferro | .73 | 173 | |
| Shiro Kashi (Japanese White Oak) | .82 | 179 | |
| Republic of honduras Rosewood | ane.00 | 189 | |
| White Ash | .60 | 196 | |
| Birch | .62 | 196 | |
| KWW Laminated Composite | i.xxx | 198 | |
| Coromondel Ebony | 1.ten | 202 | |
| Osage Orange | .fourscore | 243 | |
| Bear on Class Hickory | .775 | 345 | |
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Although high density doesn't necessarily translate into high touch on forcefulness, it has a major influence on operation and maneuverability. It is almost always desirable for Baton (police stick) , Yawara (�short stick ~12"), Kobuton (hand weapon ~five"), Tanto (wooden pocketknife) and other short sticks under 24 inches. The additional inertia is a major benefit in many defensive situations and when the weapon is used for force per unit area point techniques, dense and harder forest is much more efficient. For these applications, wood with specific gravity over 1 is often all-time.
Bokken (wooden sword) and other longer weapons used in paired practise should be chosen from a material with high bear on force. In some cases, a wooden sword is intended to approach the actual weight of a real sword and higher density materials (specific gravity greater than one) are required but these weapons should not exist used for routine practice. Suitable higher density materials are about e'er plush. Almost woods with high specific gravity is tropical in origin (the laminated composite shown in the charts comes from reasonably well managed domestic sources but is expensive nonetheless). The almost important consideration of all is the possibility of an impact which exceeds the cloth's stupor strength; a state of affairs that becomes more likely with a weapon over 24" in length and relatively slender in diameter like Bokken and Jo. High density materials are harder, with the appearance of existence practically indestructable and sometimes won't show damage prior to failure. An unexpected, complete suspension may create a unsafe situation. The aforementioned precautions are advised for very long weapons including Bo (long staff ~ 72") , Naginata (Japanese halberd like weapon ~ 96"), Yari (spear upwards to 120"), Juken (burglarize/bayonet ~ 72") etc. if used in contact with other practice weapons.
Materials
Different materials are appropriate for different weapons and dissimilar situations. The following forest selections are described and recommended co-ordinate to their individual properties:
Shiro Kashi (Japanese White Oak)
Martial artists familiar with Japanese wooden weapons oft refer to this woods simply every bit "White Oak". It has a tight but coarse grain structure and like N American White Oak, it has prominant rays which give it a distinctive figured appearance. It's either bone white or light tan in colour and darkens over time. Shiro Kashi differs in several respects from Northward American White Oak. While related, the Japanese White Oak tree is evergreen and owing to its continuous growing season, does non have a conspicuous open up grain like American White and Blood-red Oak. Open grain structure, typical of the then called "ring porous" hardwoods presents soft areas which are more prone to impact damage. Kashi is uniformly difficult, has excellent dent resistance and has better impact strength than American Oaks. There are ii drawbacks relevant to its use in wooden weapons: Information technology is not stable; weapons of Shiro Kashi will ofttimes warp due to changes in atmospheric humidity. Also, like other Oaks, it seems to lose strength as it ages. In tests conducted on older samples from woods that had been very strong, the anile material had lost its integrity substantially. The older wood will appear dry out and develop cracks usually commencement with a grain separation in areas of repeated impact - a sure sign that the weapon is weakening. Clearly, Shiro Kashi should be considered a skilful quality utility wood, splendid for several years practice but probably having a express life span.
White Ash
The most well known and useful of the Ash family is White Ash. The wood is strong in comparison to its weight and is oftentimes used for baseball bats, tool handles, oars and paddles. Ash is noted for its stability. Information technology is less field of study to twist, warp and dimensional change than virtually Due north American hardwoods.
Ash is a ring porous hardwood with strongly contrasting spring and summer wood. This characteristic results in alternate, relatively hard sections with softer areas of open grain. Because of this, Ash is more decumbent to objectionable denting when impacted on its softer areas and is non ideally suited for weapons taking direct impact. Because of its otherwise excellent mechanical properties however, and its tendency to go smoother and better with continuous handling, information technology is one of the very best materials for long shaft sections on Yari and Naginata.
Birch
Birch is moderately heavy and hard with proficient strength. Its appearance is very similar to Maple with an fifty-fifty, fine texture and tight grain structure. White Birch refers to the white sapwood of the species and Red Birch refers to the heartwood of the same tree. Birch grows throughout the hardwood forests of temperate latitudes and is an important commercial hardwood. Its loftier stupor strengh and availabiliy in thick, long pieces, making information technology a good contender for wooden Bo staff. Naginata, Yari and Juken. In its natural state, its drawback is its tendency to show impact dents where contact is heavy.
Birch is well suited to the production of veneers, In the 1950s, the US Forest Products laboratory developed a procedure of drawing resin and dyes through veneer stock and laminating the wood layers nether extremely high pressure to produce an enhanced composite product. This material is generically known equally Compreg (compressed, impregnated woods). The variation referred to in this publication is the "Laminated Rosewood Composite" of Kingfisher WoodWorks.
Touch on Class Hickory :
At that place are at least 16 species of Hickory native to Asia, Central America and Northward America. Mixed hickories, appropriate for furniture and cabinet work, are obtainable in lumberyards throughout the United States. Varieties from New England, the Midwest, Great Lakes and Southwest, including the closely related Pecan Woods, produce lumber comparable in quality to many other North American hardwoods every bit shown in the preceding impact and density charts. For lack of a better clarification, the designation "Impact Grade" Hickory refers to a source of regional varieties selected according to subspecies from a small expanse in the Central Appalachians where trees are selected that yield wood with properties suitable for martial art equipment. Not only is the material unique mechanically, it is likewise handled much differently than chiffonier grade lumber. Common grades of commercial hickory are grouped together. Commercially distributed hardwood is usually kiln dried and hickory, which is difficult to dry out, is sawn into into standard iii/4" planks which allow accelerated dry kiln schedules. These thinner planks include (mechanically) junior species of Northern and Western hickories with the added risk of structural damage caused past faster drying schedules. This special stock however, is cut into thicker slabs of the virtually premium cloth from a specific geographical area and slowly air dried. This resulting "Impact Class Hickory" is either os white or low-cal ruby-red in color. It has a flat, svelte grain structure and a shine texture with good density. Its daze strength exceeds all native and exotic species including the usually used Japanese White Oak (Shiro Kashi). While Oaks announced to go brittle with age, Weapon Grade Hickory retains its toughness. Although heavy contact with very hard materials will cause some denting, normal practise with similar weapons will simply create an unobjectionable patina. Even after years of heavy use, it is unlikely to snap into unsafe pieces. Ideally, the best Dojo choice would exist the uniform use of this material for paired practice. It'due south prophylactic, strong, attractive and comes from a domestic managed resource. Only as Kashi is the only woods used in Japan for practice weapons, American martial artists tin can look to this peculiarly graded hickory as the optimal choice.
Laminated Rosewood Blended (LRC)
LRC refers to a express, premium form nomenclature of densified hardwood composite. Made past laminating very sparse layers of imbued birch veneer under enormous pressure level, it has a stunningly beautiful dark Rosewood colour with black highlights, is totally stable and takes a mirror cease.Weapons of LRC have several notable benefits. With a specific gravity of ane.3, its extremely loftier density and hardness make it ideal for smaller weapons where those qualities are so desirable. Information technology comes from domestic sustainable sources and is an splendid substitute for rare tropical varieties. Since the intersticial spaces and microscopic conduits of the woods are filled with resin, there is picayune if whatever exchange of atmopheric wet and hence no warpage. When skillfully worked, it holds perfect detail and when polished and buffed, will accept a mirror like polish without any boosted surface treatments. Because it is extremely dense, bokken made of LRC can achieve both the weight, proportion and remainder of a live blade. It has excellent physical backdrop overall and, in the case of bokken, approaches the closest interpretation possible of a sword. It is even so, an engineered material with properties unlike from natural woods and LRC items should be treated more like alive edged weapons than those of natural woods. Since the cloth does not dent hands, it gives the impression that it is much stronger than any natural wood. As the tests show however, information technology's strength exceeds many of the strongest natural woods but not immensily and then. It tends to exist edge sensitive and an accidental drop onto concrete, which would just dent nigh natural wood may cause a more than serious chip in the blended material. While there have been many natural wood bokken destroyed when hit with a composite weapon and at least one live steel blade, at that place have also been a few blended weapons broken and a few instances where a glancing blow at the very end of the point damaged a blended bokken. For these reasons, the LRC is non recommended for paired work involving contact but improve reserved for suburi (individual) practice, silent sword techinques, presentation or other special situations.
The final consideration, as it relates to paired practise may be said of any of the very difficult and dense materials in general: In a practice situation, many students use equipment that fits their means and their experience. Very hard and heavy woods will certainly do significant damage to the budget oriented weapons that many beginning students start out with. In the interests of rubber and practiced judgement, it is best to appoint in daily paired practice with materials that exercise not crusade unnecessary damage to a partner's equipment.
African Ebony
Several tropical hardwoods including African Ebony are extremely hard and heavy but without notable touch forcefulness. Also known as Cameroun and Gabonese republic Ebony, this woods is jet black with occasional grey striping and is the familiar black wood formerly used on piano keys. Because of its density, outstanding hardness and ability to hold item, it is excellent in small hand held weapons used to employ pressure level. Along with other wood of tropical origin, Ebony comes from sources that aren't necessarily well managed, should be considered a limited resource and used judiciously.
Honduras Rosewood
There are several species of natural Rosewood with excellent density, forcefulness, dent resistance and overall physical properties. Honduras Rosewood is usually a dark reddish tan sometimes with prominant streaks of black and imperial. It has a cute, coarse swirling grain construction with color patterns varying from reserved to startlingly bold. Rosewood is non often available from sustainable sources in pieces suitable for solid construction larger items. Smaller Tanto, Kobuton, Yawara and similar works are often possible. Bokken and Jo of natural Rosewood are highly desirable and extremely rare. This textile, like other tropical woods is not recommended for daily do or coincidental employ due to its scarcity and unique graphic symbol.
Pau Ferro
South American Pau Ferro (Ironwood) has a beautiful night tan colour oft including black streaks and graceful night figure patterns. It has fine, dense grain with a very smooth surface texture. Pau Ferro, an exceptional and rare tropical wood, is occasionally available in pieces thick enough for solid piece bokken and jo and it makes excellent blade sections for Yari and Naginata intended for presentation and solo practise.
Purpleheart Wood
Purpleheart is available in thick pieces which allow for the construction of largest and longest solid piece weapons. It is sometimes possible to obtain information technology from managed sources and has some outstanding backdrop making it especially suitable for staff type weapons like jo, bo etc. It is very hard, and commonly displays a straight, uniform grain structure with a somewhat coarse texture. It turns to a clear, brilliant violet upon exposure to light. Purpleheart is extremely stable and lends itself to long, slender weapons where a less stable material would usually develop noticeable warpage. Because it is extremely potent in comparison to its weight, it gives the user an energetic feel of returning energy rather than absorbing it and for these reasons, could be considered a "conditional wood" - an excellent choice for some situations.
Coromandel Ebony
Besides known equally Macassar Ebony, this infrequent wood deserves special consideration among the natural woods bachelor for the construction of wooden swords, staffs and martial art weapons. Because of its superb graphic symbol, it conveys a unique and unmistakable feeling of presence. Coromandel is stiff, hard, has a platonic weight with a fine dense texture. If skillfully shaped and finished, an alive nearly reptilian quality emerges with predominantly black with tan figure patterns and occasional subtle but surprising hints of green and other colors. It is arguably one of the most beautiful of all woods.
Upon reading this description, it may be tempting to conclude that a fine weapon of Coromandel Ebony is the optimal personal choice for the serious student of the martial arts. Its unrestricted use however, would actually be inappropriate. Acquiring unique and rare weapons of limited natural resources oftentimes reflects the enthusiam of aspiring students where, due to the cost and scarcity of this material, is all-time reserved for special situations - a gift perhaps to a senior instructor from an appreciative dojo.
Osage Orange
No word of wood, selected for weight and force, is complete without mention of Osage Orangish, an unusual N American hardwood with a unique heritage. Indigenous to the American Southwest, the wood has a superb strength and was highly prized by Native Americans for archery bows and is notwithstanding coveted by traditional bowyers. When freshly cutting, it has a startling and unlikely bright yellow color which slowly turns to a subdued orange tan. The tree does not produce much of the dumbo, straight grained wood which has adept mechanical properties. High quality lumber is very rare merely the tree is certainly not endangered. Other studies of shock forcefulness sometimes rate Osage Orange as the strongest of all forest. When used in longer weapons for paired exercise it absorbs energy upon impact with a surprising springy feel.
Under the proper name Kingfisher Woodworks, James Goedkoop has produced thousands of practice weapons for aikido practice and the sword related martial arts.
This article was first printed in the May/June 1999 edition (Upshot #63; Vol 13, No. three) of Aikido Today Magazine and is reprinted with their permission.
Source: http://www.aikiweb.com/weapons/goedkoop1.html
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