Announcement

Collapse
No announcement yet.

Does an extra deep groove make a weight difference

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Does an extra deep groove make a weight difference

    I am looking to buy my first iaito and I was going to go for a Tozando custom iaito. I see that the weight jumps up from 845 to 1015g as I will need a 2.50 shaku blade. Does anyone know if paying for the extra deep groove make much difference to the weight? Cheers.

  • #2
    Tozando has English speaking staff who you can ask for specifics. In my opinion, the better question to ask is "where is the center of balance?" A well balanced iaito will have this point at approximately 10cm from the tsuba along the blade. Much further out and it will feel more tip heavy. On a 2.50 shaku blade you're unlikely to have the center of balance too far in. My sensei's shinken is heavier than my mogito but feels lighter when cutting as it has remarkably good balance. So I would ask them where the center of balance would be with your desired options and if need be, choose other options (heavier or lighter tsuba is the obvious way) to get the balance right.

    Comment


    • #3
      HI dillon, thanks a lot for the reply. I know Tozando has English support but i wanted to post here in case there were other views to this and the balance was not what I actually focused on as i was thinking purely on the weight so thanks for that advice. I will make sure i now contact Tozando and ask them that.

      Comment


      • #4
        Just a tangential point but if you are importing iaito into the UK, you'll need to consider the restrictions on "samurai swords". When I lived in London this had just came in when I ordered a mogito so I emailed to the supplier some documents and asked them to pack these with the shipping invoice and another copy with the goods (in anticipation of actions by customs agents). The docs were a letter addressed to customs about the sword ban and exemption for martial arts (and how to contact me if there are questions), a copy of the relevant statute pointing this out, and copies of my current affiliation records and third-party insurance. It's good to keep these with you when going out of the house with your weapons too. Check the BKA or whoever is your federation for guidance. There is info on what to do if stopped by police, etc.

        Comment


        • #5
          Thanks for the warning but I live in the Netherlands so no such issues here except paying an import duty. I still have a wall hanger which i bought like 25 years ago which is still at my parents in the UK and I tried to post it over but no one would touch it or I faced the chance of customs opening and destroying it.

          Comment


          • #6
            There's a great new book out called 'Analysis of the Iai Katana' by Jon Andreson. I think this might be the most important work on Japanese swords I've ever come across. Its engrossing and if you're the sort of person who loves looking at data and graphs and standard deviations and this-plot-and-that then you will love this book. It is, essentially, a quantitative characterisation of Japanese swords from across the significant sword-making eras of Japan (Heian to Heisei). The author measures various characteristics of typical swords from each era and compares them using various plots and manipulations - you name it, the various parameters are plotted into meaningful graphs that give the reader such in-depth data as to leave them reeling in ecstasy! Some are obvious; nagasa (length) vs weight but others like sori (curvature) vs bohi (groove) less so but insightful nevertheless. One could make meaningful predictions about a Japanese sword's characteristic's by using these data or extrapolating them-an amazing tool. To make things even more useful, the author analyses the various types of timber used in making bokuto (often the first 'sword' an Iaidoka will encounter), disambiguates the various species names for the timber, evaluates their properties and usefulness in making a good practise sword....fascinating. At the end of the book the author provides more wonderful data on caring for your Japanese swords with suggestions on substances better than choji oil for protecting your blade from corrosion and better alternatives to horribly abrasive uchiko powder. I love this book since its dispassionate in it's presentation of data, its transparent in its presentation of data and it presents lots of data. I love Japanese swords, I love quantitative data! If I were to make one small criticism, I'd say the book could be improved by including more photos of sword's characteristics discussed in the text, but it's a small criticism.

            Comment


            • #7
              Thanks for mentioning my book Kokoro777, I'm glad to know someone found it useful!

              To answer the original poster, yes, deeper bohi will reduce the weight of the sword as long as nothing else is changed. I might add that 1015 g (fully mounted, not bare blade) is not heavy for such a long sword. Anyway, the bohi will not only affect the weight but the moment of inertia, which is commonly called "balance". All other things being equal deeper bohi will lessen the moment of inertia making the sword feel less tip heavy while in motion. It may still feel heavy when holding it still but the perception of the swords weight when in motion will be less. As an aside, nobody ever measures moment of inertia and instead use the static balance point as a proxy for moment of inertia.

              Changing the tsuba is probably an easier way to adjust the moment of inertia. Blade feel tip heavy when cutting?--then put on a heavier tsuba and visa versa. Have to say that very long swords normally feel more tip heavy than shorter swords, that just comes with the territory and a 2-5-0 sword is a very long katana.

              Comment


              • #8
                double post edit.

                Comment


                • #9
                  Originally posted by jandrese View Post
                  Thanks for mentioning my book Kokoro777, I'm glad to know someone found it useful!
                  I'm glad I didn't say anything nasty about your book! I really do like it. The use of choji alternatives is a really excellent piece of advice.

                  Originally posted by jandrese View Post
                  Changing the tsuba is probably an easier way to adjust the moment of inertia. Blade feel tip heavy when cutting?--then put on a heavier tsuba and visa versa. Have to say that very long swords normally feel more tip heavy than shorter swords, that just comes with the territory and a 2-5-0 sword is a very long katana.
                  I've this is as a solution but of course this will add to the overall weight of the sword. Isn't that a problem? Or are we talking about very small weight increases in the tsuba?

                  Comment


                  • #10
                    Originally posted by Kokoro777 View Post
                    I'm glad I didn't say anything nasty about your book! I really do like it. The use of choji alternatives is a really excellent piece of advice.

                    I've this is as a solution but of course this will add to the overall weight of the sword. Isn't that a problem? Or are we talking about very small weight increases in the tsuba?

                    Modern choji oil is really just light mineral oil, which is okay but there are better oils. Right now I'm really experimenting with the Lubriplate FMO oils. The 350 weight coats really well, is totally colorless but can feel "dry" when practicing iaido due to slightly higher viscosity. The 200 weight feels wetter and more slippery when using a sword for iaido because is a better viscosity match for choji oil. Maybe I'll store in 350 and practice with 200. So many choices with modern, fortified oils.

                    Regarding the tsuba, yes, adding a heavier tsuba will make sword more massive. Better feel in motion is what we are after however so totally worth it. Many times having a tsuba that is only 50 g (or less) heavier will make a huge difference in moment of inertia.

                    Sword weight is a bit of an issue for me. Many iaido folks use really slight swords, which is their business, but they will also call my swords heavy. They are not, I have the data. I weight 210 lbs so a 2.5 pound sword should really not be an issue, and for me it's not. Even if I weighted 120 lbs a katana should pose no problems. It's all about the technique and recognizing that katana are not rapiers. Samurai did not use rapiers, katana is totally different. Not better, not worse, just different. Before the modern era very slight katana sold for the express purpose of practicing iaido did not exist.

                    Comment


                    • #11
                      Originally posted by jandrese View Post

                      All other things being equal deeper bohi will lessen the moment of inertia making the sword feel less tip heavy while in motion. It may still feel heavy when holding it still but the perception of the swords weight when in motion will be less. As an aside, nobody ever measures moment of inertia and instead use the static balance point as a proxy for moment of inertia.
                      .
                      Hi Jandrese, thanks so much for the reply (and okoro77) so is the sword feeling less tip heavy a good or a bad thing? Thanks.

                      Comment


                      • #12
                        Originally posted by jandrese View Post
                        Sword weight is a bit of an issue for me. Many iaido folks use really slight swords, which is their business, but they will also call my swords heavy. They are not, I have the data. I weight 210 lbs so a 2.5 pound sword should really not be an issue, and for me it's not. Even if I weighted 120 lbs a katana should pose no problems. It's all about the technique and recognizing that katana are not rapiers. Samurai did not use rapiers, katana is totally different. Not better, not worse, just different. Before the modern era very slight katana sold for the express purpose of practicing iaido did not exist.
                        That is because before the modern era, there were very few people that only practiced iaido for a couple of hours a week. These pre-modern people also did not have jobs that required repetitive use of the hands, wrists, and elbows as working on a computer does. Utilizing light swords to lessen the chance of repetitive stress injuries is not a bad thing, and should never be looked down upon by those in positions of authority.

                        Originally posted by dodgyoshitsune
                        ... so is the sword feeling less tip heavy a good or a bad thing? Thanks.


                        It has been my experience that it is more of a personal preference sort of thing. A tip heavy sword is much easier to cut with, and is good for learning how to launch your sword where it should go and letting it do the work. A more back-weighted sword is easier on the shoulders and elbows, but can lead to bad habits of trying to guide the sword overly much.

                        Comment


                        • #13
                          Originally posted by pgsmith View Post


                          It has been my experience that it is more of a personal preference sort of thing. A tip heavy sword is much easier to cut with, and is good for learning how to launch your sword where it should go and letting it do the work. A more back-weighted sword is easier on the shoulders and elbows, but can lead to bad habits of trying to guide the sword overly much.
                          Thanks for the feedback pgsmith. Is there any downside to a tip heavy sword? I know that with the sword I am going to be ordering from Tozando (custom iaito 2-50 shaku) and I am average built guy so I was thinking on getting the extra deep groove to cut down the weight (Tozando said it was about 30g off the 1015g) but not sure if it will really be worth it after all. I also know I cannot hold or swing the sword which is why I am trying to gather some opinions. Cheers.

                          Comment


                          • #14
                            I have a tip heavy 2.45 Tozando custom that is my first and still current iaito. Learning to stop the blade where it is supposed to (e.g. at horizontal) was a struggle (maybe 2years before the fault got ironed out). I didn't have that problem when I tried with my sensei's heavier but very well balanced shinken. So that was two years learning to compensate for a forward balanced blade. If I had done koryu at that time I would have dinked the flooring constantly no doubt.

                            Comment


                            • #15
                              Thanks for the feedback dillon, its good to hear. When I read all the feedback and comments on Tozando's site all the persons say how well balanced it is, no one mentioned tip heavy. I was also looking through some other makers sites and their iaito's of the same length are all around the 900g mark.I guess its a gamble if the extra deep groove affects the balance making it more tip heavy.

                              Comment

                              Working...
                              X