Better a bald head than no head at all.

Seamus MacManus

In the previous post in this series about Japanese hammers we examined a feature found in all modern hammer heads: the essential, unblinking, unseeing eye. In this post we will touch on the style of heads recommend for using with Japanese chisels. We discussed this subject in this post as well.

Gennou Head Shapes

The most popular head shapes commonly available in Japan nowadays are: ryoguchi, daruma, funate, yamakichi and various hybrids thereof.

Ryouguchi

Ryouguch is the most common style of head, at least in Eastern Japan. It has two faces: A flat one for striking chisels and nails, and a slightly domed opposing face for kigoroshi and setting nails below the surface of boards.

While a simple design, this style of head has a relatively high moment of inertia, making it is more stable than other styles and therefore less likely to twist out of alignment during the swing, or twitch upon impact, a positive thing if you are a card-carrying member of NBA (Nail Benders Anonymous). (ツ)

Face designs in this style vary widely including round, oval, square, rectangular (usually with corners removed for a more octagonal shape) true octagonal, and the “Ichimonji” style with roundish sides and a flat top and bottom. We prefer the rectangular shape with cut corners best, but one style is no better than another. We don’t recommend, however, faces with 90 degree corners as the corners are counter-productive during kigoroshi operations and are structurally weaker.

If you are worried about pulling nails, we encourage you to use a nail bar to reduce the number of broken hammer handles wandering the world sad and lonely as a cloud.

The Daruma

The Daruma (pronounced dah/rhu/mah) gennou head takes its name from a famous Buddhist priest of oval stature who lost both arms and legs through excessive meditation, a blessed state doubtless achieved by many of our enlightened Beloved Customers (spiritual enlightenment that is, not quadriplegia). This gennou head is a stubbier version of the ryouguchi gennou, and always has a round face.

It’s more popular outside of Japan than domestically, for reasons your most humble servant fails to understand. From a physics viewpoint, at a given weight and because of its lower moment of inertia, it is less stable than other styles of gennou, but because it has a bigger face, and is intended to be used at constantly differing angles such that stability is less critical, this style is preferred by carvers. Joiners like it too for cutting repetitive mortise and tenon joints, but it is not favored by most other trades and may invite remarks at jobsites from other workers about the owner being unable to find his derriere with a mirror on a stick and a GPS. That said, your humble servant frequently uses daruma heads for cutting precise mortise joints in joinery.

An 80monme/ 300gm/ 11oz daruma head with an rock maple handle.

The Funate

The funate gennou is closer in appearance to Western hammers with a skinnier neck behind the striking face, but without the split-tail “piano chisel” a foreman from my misspent youth named Jack Frost called the claw on his 28oz waffle-face framing hammer.

The funate gennou is more commonly seen in the Western Japan than Eastern Japan where I learned Japanese woodworking. It’s useful for finish work involving nails and for tapping-out plane blades, but less useful for wacking chisels.

The Yamakichi

Yamakichi was the name of a gennou blacksmith working in Fukuoka on Kyushu Island that originated this style of head and gave it his name. Kosaburo introduced this style to Tokyo in response to customer demand and with Yamakichi’s permission, we are told, improved the design somewhat.

This style is a heavy-duty stubbier version of the funate with a slightly domed face and a kinda sorta pointy tail, perhaps better suited to starting/setting nails than the ryouguchi head, but certainly better for striking chisels than the funate style.

Better with nails than the ryouguchi style, this head makes an excellent all-round hammer for working in the field, and can even handle tapping-out tasks.

The design has a unique and interesting appearance which reminds this humble scribbler of a 1956 Ford F100 truck in that, while neither sleek nor smooth, it has a sculptural quality not seen in the other styles that “grows on you.” It feels good in the hand too.

There are other in-between head shapes, but these are the four basic styles generally available for woodworking today.

Weight

The subject of gennou head weight was examined at some length in a previous post.

Regardless of the type of gennou head you select, weight is a critical factor that will depend on what you plan to hit, your height above the thing you are hitting, how hard you need to hit it, and how precisely you need to hit it. Your own practical experience is the best basis for selecting the genno weight for a particular job, but some guidelines can be suggested.

To begin, the traditional measure used for gennou in Japan is the “monme,” with 100 monme equaling 375 grams or 13.2 ounces (1 ounce = 28.35 grams). 

The standard middle-of-the-road weight for gennou used by carpenters in Japan ranges from around 100monme (375grams/ 13.2 ounces) to 120monme (16oz). The most common hammer used for finish carpentry in the United States weighs 16oz. So if you are going to buy your first gennou, and you intend to use it for general finish carpentry or furniture making, a 100 or 120 monme head is a good place to start. 

For finer work, 50-80 monme (7~11 oz) is a good choice. If you intend to make furniture or joinery, one in this weight range is a must-have.

For cutting deep mortises in heavy timbers with large chisels, as in timber framing or boat work, a 200monme (26oz) hammer is frequently used, but 250 (33oz) and even 300monme (40oz) heads are available. I own and use them when necessary.

Some factors to consider when selecting a heavy gennou are that with greater weight comes greater impact force, and greater penetration, but heavier gennou are more tiring to swing and harder to control precisely, especially depth of cut.

Other factors to consider are the weight of chisels to be used, the width of their blades, and the hardness of the wood to be cut because a heavier chisel with a wider blade cutting white oak requires more force to cut to a given depth than, for instance, a 3mm oiirenomi (bench chisel) cutting sassafras. Only experience can instruct Gentle Reader what weight will work best in a given situation. Just be aware that, unlike athletic socks and gubmint health care (aka medical fraud collusion), there is no such thing as one-size-fits-all.

Conclusion

We hope this article has answered some of Gentle Reader’s questions on the subject of selecting a gennou head. If you have additional questions or need clarification, please use the “Leave a Reply” form below.

In the next article in our ongoing quest for spiritual enlightenment and metaphysical stability we will discuss the differences between mass-produced and hand-forged gennou heads. We will also consider the necessary attributes of woods suitable for making handles along with more design details in future posts, I promise. Until then, I have the honor to remain,

YMHOS

The following link is to a folder containing pricelists and photos of most of our products. If you have questions or would like to learn more, please use the form located immediately below titled “Contact Us.”

Please share your insights and comments with everyone by using the form located further below labeled “Leave a Reply.” We aren’t evil Google, facist facebook, thuggish Twitter, or a US Congressman’s Chinese girlfriend and so won’t sell, share, or profitably “misplace” your information. May my toes all grow black, stinky mushrooms if I lie.

I do think a carpenter needs a good hammer to bang in the nail.

Oliver Reed

Introduction

This is the first in a series of articles about the Japanese gennou hammer in general (written 玄翁 in Chinese characters and pronounced “gen/noh”) and in particular how to design and make a unique one that perfectly fits your body and style of work.

The objective of these articles is to share with you, Gentle Reader, what your humble servant has learned over the years about gennou handles to help you design and make your own.

I will gladly share the entire series, including the drawings, as a single document with Beloved Customers upon request.

The True Craftsman Makes His Own Tools

A handful of generations ago quality high-carbon steel was difficult to make and expensive, so woodworkers worldwide, especially Japan, could not afford many tools, and the ones they did own or inherit were very important to them.

At least partly to reduce costs, it was standard practice back then for a woodworker (or his master) to commission the metal parts of his tools, such as the heads of his axe, hatchet, adze and hammer, and the blades of his chisels and planes from the local blacksmith. In the United States or other British colonies a craftsman may have purchased chisel and plane blades imported from Sheffield, but he would not want to pay the high costs of shipping wooden components across oceans and over mountains when he could make them himself. After all, woodworking was his business, so a self-respecting craftsman would make all the wooden components of his tools himself as a matter of course. Needless to say, those old boys knew how to make handles.

But things have changed. You may not realize it, but we live in a time of extreme wealth where even the poor live better than kings did 200 years ago, partly due to widespread industrialization making the necessities of life, and even what would have been called luxuries, available to everyone cheaply. This industrialization combined with cheap transportation has resulted in the prevalence of craftsmen purchasing pre-manufactured things, including tool handles.

Accustomed to the easy availability of standard mass-produced tools, lacking a clue about performance and focused like a laser on lowest cost, most woodworkers nowadays get by with colorful but poor quality tools designed by kids using computers working in marketing departments that have never used a handtool professionally, and fabricated by farmers in Chinese factories from higgily-piggily scrap metal. These tools may look great on the internet or wrapped in theft-proof plastic containers hanging on pegs in the big-box retailers, but how do they perform? And how long will they last? And what do they say about the men using them? Tools are terrible gossips, you know.

Gentle Reader cannot purchase a hammer handle like the one we will discuss in this series, and no one can make it for you. A hand-forged gennou head fitted with a handle made in accordance with the guidelines presented in this series will become a unique lifetime tool and the sure sign of a superior craftsman. More importantly, it will help you work more efficiently and precisely, make the joints in your shoulders, arms and hands hurt less, and give you greater confidence in your skills.

If you think this all sounds too good to be true, I challenge you to put it to the test. In fact, there is a series of performance tests listed in the last post of this series (when it is published, see link at the end of this post) that will allow you to generate hard proof of the truth of these claims for yourself. You will be impressed with the results.

While Japanese hammers are the primary focus of this series, you can apply the ergonomic principles and solutions I will describe to all varieties of hammer handles.

Modern Tools: Marketing, Design & Manufacturing

I grew up using hammers designed for maximum sales in a competitive marketplace of amateurs, of the type I call “One Size Fits Nobody.” Back then they were made in the USA, but nowadays they are cheaply mass-produced in China. Prices are rock-bottom, and quality is focused solely on getting an attractive product to the big-box retailers at the right price-point while fending off the slavering hordes of snaggle-tooth lawyers that specialize in product liability and personal injury lawsuits. To these corporations, you and I are beasts in a herd, of no import beyond the contents of our wallets and our willingness to empty them.

Like the cover of a manga comic book, mass-produced modern tools are carefully designed to immediately draw the eye and excite the senses of those passing by. Bright colors and futuristic shapes war with each other for attention on the pegboards of big-box retailers. Handles are made of plastic and rubber fitted over cast steel or molded fiberglass, secured with globs of glue intended to hide malformed ulcerous eyes.

The designers of these blister-makers and nail-benders intend their products to age poorly so they will be discarded by purchasers after just a few years to ensure unending sales of “new-and-improved” replacements. Plastic and rubber are the materials of choice because they are cheap to fabricate, easy to make into colorful, exciting shapes, and speedily surf the spiral wave into the depths of the toilet of planned obsolescence. 

The international playboy that Billy Crystal introduced the world to in “Nando’s Hideaway” might have been talking to one of these hammers when he said “This is from my heart which is deep inside my body: You look mahvelous, absolutely mahvelous dahling. Remember, it is better to look good than to feel good.”

Perhaps these tools do look mahvelous hanging on those pegboards. But how good do they feel?

The tool conglomerate’s product development departments and marketing geniuses have taken the Latin Lover’s philosophy to heart. They know that tools that look good and turn to garbage quickly are more profitable than efficient tools that merely feel good. I am sure ‘Nando would go “crazy nuts” if he observed modern hammers in their natural environment, but alas my friends (saludos, my darlings, you know who you are), Nando will not make the journey to a big-box home center to inspect their pegboard tools because he does not feel good.

Clever people, these marketing strategists, stuffing their pockets with money and landfills with plastic and scrap metal by selling imitation tools to the herd. But as for me, I’ll have none of that churlish fraud, thank you very much.

Hammer Handle Morphology

The hammer is an extremely simple tool, literally as old as humanity. I suspect humans made the first multi-component tools by attaching wooden handles to stones to make hammers, axes and clubs. 

But despite millennia of history, modern folks have all but forgotten how to make a proper tool handle. It wasn’t always that way.  Everyone made their own replacement handles only five generations ago, and their expectations were guided by sweat and blisters. They didn’t need product development departments in Shanghai to tell them what handle worked best.

Axes are an obvious example of how marketing has morphed handle design. Take a gander at an old tool catalog and notice how axe handles have become thicker in the last 120 years. Do these changes mean that for millennia humans didn’t know how to use axes or make proper handles for them? Do modern human joints and tendons endure the higher vibration and impact forces a thicker, heavier, stiffer handle transmits better than those of our forefathers? Has the nature of modern trees changed such that grain runout no longer weakens a needlessly recurved handle made from their wood?

No, these recent changes in handle design are not intended to make tools more functional or more durable, but are rather to increase sales of cheaply mass-produced tools of apparently innovative design, mediocre quality and disposable utility. They simply look mahvelous, absolutely mahvelous dahling, especially as a picture on a website or hanging on a peg in a hardware store.

Please, don’t get me started on modern mass-market saw handles.

In the next article in this series about beaters we will look at the ergonomics of hammers. Until then, I am profoundly honored to remain,

YMHOS

PS: Here is an excellent article about the “Devolution of Axe Handles” that jives well with my research and experience, and the advice my grandfather gave me about making an axe handle 50+ years ago. And just to prove that we at C&S Tools have refined tastes, here’s some music from Fernando.

The following link is to a folder containing pricelists and photos of most of our products. If you have questions or would like to learn more, please use the form located immediately below titled “Contact Us.”

Please share your insights and comments with everyone by using the form located further below labeled “Leave a Reply.” We aren’t evil Google, facist facebook, thuggish Twitter, or a US Congressman’s Chinese girlfriend and so won’t sell, share, or profitably “misplace” your information. May I never know love or sunshine if I lie.

Subsequent Posts in The Japanese Gennou & Handle Series

• Part 1 – Introduction
• Part 2 – Ergonomics
• Part 3 – What is a Gennou?
• Part 4 – The Varieties of Gennou: Kataguchi, Ryoguchi & Daruma
• Part 5 – Kigoroshi
• Part 6 – The Ergonomic Anaya
• Part 7 – The Unblinking Eye
• Part 8 – Style & Weight
• Part 9 – Factory vs. Hand-forged Gennou Heads
• Part 10 – Laminated Gennou Heads
• Part 11 – Decorative Gennou Heads
• Part 12 – The Drawing: Part 1/6
• Part 13 – The Drawing: Part 2/6
• Part 14 – The Drawing: Part 3/6
• Part 15 – The Drawing: Part 4/6
• Part 16 – The Drawing: Part 5/6
• Part 17 – The Drawing: Part 6/6
• Part 18 – Wood Selection