I left my Jo (white oak, 1 inch diameter, 51.5 inch length) leaning in the corner for two years. Now I'm using it again and it is noticably bowed and deformed. While it is straight "enough" to be functional, I don't like it.

Some people have told me if I suspend it between two points and put a weight on it it could in time (weeks) bend it back. Other people have told me they haven't been successful with that method.

Is there any to repair the weapon and make it straight again?

  • Maybe take advantage of the curvature and turn it into a bokken? – Petruza Mar 14 '20 at 22:41

More often than not, it's not worth the trouble (unless you're sentimental about the staff). A white oak jo is not terribly expensive.

@Campbeln is right. Here's one way to straighten a warped jo:

What you'll need:

  • Three 1x4s longer than the jo
  • One large wooden clamp for every foot of the jo.
  • Boiled linseed oil

What to do:

  1. Sand the jo. This will expose the pores of the wood.

  2. Fill a basin longer and wider than the jo with salt water near saturation (this is enough salt that it dilutes in water. Fill the basin up enough to cover the jo, add salt until it no longer dilutes, then add just enough water to make it dilute)

  3. Place the sanded jo into the bath overnight. The salt water will permeate the wood quickly and cause it to swell.

  4. Remove the jo from the water and towel dry.

  5. Place the jo on a flat surface. Clamp two 1x4s on the sides, and one on top of the jo. Clamp directly over the ends of the jo and about every foot in between to give fairly even pressure.

  6. Allow to dry. Depending on the climate, this may take a while (a week or a month in some cases). When the outside of the wood appears dry, move to step 7. Do not attempt to accelerate the drying process unless you have a wood dryer (at which point, why do you need this?).

  7. Remove from clamps and blocks.

  8. Store someplace flat and do not use for about 6 months. This will give it time to dry completely.

  9. Before use, sand again and rub with boiled linseed oil.

So now that you've seen you're about to invest either some serious money or ridiculous time into this little misadventure, it might be time to just break down and buy a new jo.

  • 2
    "So you're saying there's a chance." – Jack B Nimble Jun 7 '12 at 17:14

While @slugster is most likely correct (though as you're not likely to take it into battle, I don't think it's a huge issue if the integrity is effected slightly), my grandfather used to intentionally warp wood for furniture using a saltwater soak for a number of hours (days?) then placed the wood into a frame for shaping. This may be do-able in the reverse.

I do not know the specifics (nor can I ask as he is no longer with us), but I'm sure you could find info online regarding wood warping for furniture/etc.

Best of luck!


While there are various ways to remediate wooden items in general (hot water, weights, braces, etc.), I don't believe there is a way to properly fix your jo without compromising its strength.

It is most likely either moisture or direct heat and (sun)light that caused the warping - assuming that it really is white oak (and not a similar softer wood just sold as white oak). Personally I would donate it to the dojo for general use and purchase a new one - try and get one that has a cover to keep it in.

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