Manufacturology

Ironmaking at the National museum of science and technology, Stockholm 2005

Iron­mak­ing at the National museum of sci­ence and tech­nol­ogy in Stock­holm 2005. I’m com­press­ing the loupe while Robert holds it with a pinch.

Back in 2005, I took part in an event at Tekniska museet (the National museum of sci­ence and tech­nol­ogy) in Stock­holm where we demon­strated pre–industrial Swedish and Japan­ese tech­niques for iron and sword mak­ing. Quot­ing another post that I wrote two weeks ago:

Those of you who read Swedish may have seen that there is a page on my blog called “Svär­dens mästare”, which trans­lates to “Mas­ter of the swords” in Eng­lish. I trans­ferred this page with­out fur­ther ado from my pre­vi­ous web site and have yet not taken the time to trans­late and rework it. The page is a brief account of an event at the National museum of sci­ence and tech­nol­ogy in Stock­holm in 2005 where Swedish and Japan­ese met­al­lur­gists, sword­smiths and oth­ers par­tic­i­pated. Myself I was respon­si­ble for the con­struc­tion and oper­a­tion of a shaft fur­nace rep­re­sen­ta­tive of pre–industrial iron making.

I finally decided to remove that old page. I’ve there­fore decided to write this fairly lengthy post for future record. Below, you’ll find some infor­ma­tion about, and pho­tos from, the event, which took place at the National museum of sci­ence and tech­nol­ogy in Stock­holm on Sep­tem­ber 10 and 11, 2005.

Prepara­tory activities

As men­tioned above, a lot of par­al­lel activ­i­ties took place dur­ing the week­end at the museum. How­ever, from my per­spec­tive, the most impor­tant activ­ity was the con­struc­tion and oper­a­tion of a coal–fired shaft–type bloomery fur­nace. I had been involved in the plan­ning of the event since sev­eral months, and I and the fur­nace group mem­bers, who were stu­dents at Högskolan Dalarna by that time, had learned and prac­tised fur­nace con­struc­tion and oper­a­tion in advance.

I’m oper­at­ing the bel­low at Ham­marede smithy. (Click to enlarge.)

Two small ingots — the result of our two runs dur­ing our stay at Ham­marede. (Click to enlarge.)

Dur­ing the sum­mer we had been on a two day camp at Ham­marede smithy to learn from the expe­ri­enced K.-G. Lind­blad who had been mak­ing bloomery fur­naces for 20 years. We had then con­structed and oper­ated a fur­nace in Bor­länge only a few days prior to the event at the museum.

Under K.-G.‘s super­vi­sion, we man­aged to com­plete two runs at Ham­marede. K.-G. also helped us to forge the loupes, or blooms, into small ingots of about 1.4kg each. The loupe is first com­pressed on a stump in order to make use of the heat from the fur­nace as seen in the big pic­ture at the top of this post. After that comes a lot of hard work in the smithy before you have those beau­ti­ful com­pact ingots seen above.

After the sum­mer we built a new fur­nace in Bor­länge which was to be demon­strated dur­ing the intro­duc­tion of new stu­dents at the Mate­r­ial design pro­gramme.

Our fur­nace in Bor­länge, built on Sep­tem­ber 1. (Click to enlarge.)

Our fur­nace was a copy of the one we used at Ham­marede. Vari­ants of this fur­nace type has been used since the iron age, and was, despite the inven­tion of the blast fur­nace, still used for small scale iron mak­ing until the 19’th cen­tury in some areas. A patent for an improved fur­nace, sim­i­lar in prin­ci­ple but fired with stone coal instead of char­coal is described by Her­bert (1849). Appar­ently this fur­nace was still con­sid­ered indus­tri­ally impor­tant in the early 19th century.

Iron loupe pro­duced in our fur­nace in Bor­länge. (Click to enlarge.)

We were encour­aged when, despite some dif­fi­cul­ties, we man­aged to pro­duce a nice iron loupe.

The height of the ver­ti­cal shaft was deter­mined from our design with two lay­ers of ver­ti­cally stand­ing bricks put on top of each other. The shaft was sup­ported by an insu­lat­ing layer of gravel con­tained inside a log wreath. The arrange­ment of bricks can be seen in the draw­ing and photo below. The photo shows the con­di­tion of the fur­nace after the run on Sep­tem­ber 2. We had quite a bit of a prob­lem to get the loupe out of the shaft, which resulted in severe dam­age to the furnace.

My own hand made draw­ing of the fur­nace with bel­low in place.

Dam­ages after dif­fi­cul­ties to get the loupe out of the shaft. (Click to enlarge.)

Peter Mats­son made the wreath for the Bor­länge fur­nace seen above. The fancy log wreath seen in the pic­tures below from the museum was made by a pro­fes­sional carpenter.

The fur­nace at the museum

On Mon­day, Sep­tem­ber 5, I drove from Bor­länge to Stock­holm together with Robert Ståhl to con­struct the fur­nace at the museum. We brought a trailer fully loaded with tim­ber, bricks, clay pow­der, as well as the tools needed for con­struc­tion and oper­a­tion. I had also arranged for one m³ of rough gravel, as well as a pal­let of char­coal, to be deliv­ered in advance at the museum.

Dur­ing Mon­day we con­structed the fur­nace that would be used dur­ing the next week­end. The shaft was laid with clay and ver­ti­cally stand­ing bricks. It was lined with clay on the inside and a log wreath was used to con­tain the insu­la­tion, con­sist­ing of approx­i­mately 300kg gravel and soil that we dragged across the museum’s yard in 10 litre buckets.

Brick­lay­ing is a messy story. The mor­tar con­sists of clay, sand and horse manure (if avail­able), mixed with water to a fairly loose bat­ter. The best fin­ish is obtained if you work with your hands as the mor­tar is placed on, and smears with water so that the sur­face becomes smooth and fine. When then fur­nace is ready, it is dried through slow heat­ing by wood with­out blast­ing, until the moist has been dri­ven out of the mud. At this stage, heat­ing should be quite cau­tious in order to avoid cracking.

Then, on Fri­day Sep­tem­ber 9, we went again with a fully loaded trailer from Dalarna in the direc­tion of Stock­holm. More than a few peo­ple were prob­a­bly turn­ing their heads when we passed, because the trailer was dom­i­nated by a large bel­low — our newly built two cham­ber bel­low with an esti­mated blad­der capac­ity of up to 800 litres per minute. In addi­tion, we brought fire wood, iron rods, pli­ers, some stumps and other stuff needed for the fur­nace operation.

The fur­nace at the museum with Kim Svens­son and Peter Mats­son. (Click to enlarge.)

Lift­ing the loupe from the shaft for com­pres­sion on the stump. (Click to enlarge.)

We made one run each on Sat­ur­day and Sun­day. Each time we charged a total of about 10kg ore added in amounts of about 1kg every 20 minute. For each charge, we added about twice the amount of char­coal. Dis­charg­ing of the loupe was sched­uled for two o’clock, and by that time a fairly large crowd had gath­ered to see the show. This time we man­aged to get the loupe out of the fur­nace with­out too much trou­ble. Worse was that the process took longer than expected, but the crowd seemed to be patient and peo­ple stayed around until the end.

Com­press­ing the loupe on Sep­tem­ber 11. Kim holds the pinch, I swing the ham­mer. (Click to enlarge.)

About 1500 peo­ple paid the entrance fee to visit the museum dur­ing the week­end. An unknown num­ber of peo­ple chose not to pay the entrance fee, happy to stroll around and look at the activ­i­ties outdoors.

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What makes an excellent study environment?

Student’s at Kyoto Art Cen­tre. Click to view orig­i­nal. (Taro416/CC BY-NC-ND)

After sev­eral days of volcano-related writ­ings, it’s time I return to some­thing that’s closer to my “core com­pe­tency”. As a uni­ver­sity lec­turer and researcher I’m involved in both stu­dent recruit­ment and improve­ment of the study envi­ron­ment at my work­place. Per­haps the most impor­tant ques­tion that I and my col­leagues face on an almost daily basis is: How do we cre­ate an excel­lent study envi­ron­ment that helps us attract new and keep exist­ing students?

If you’re a stu­dent, this may come as a sur­prise to you, but I can assure you that it’s very hard to know what stu­dents really think of their edu­ca­tion. That means that it’s dif­fi­cult to know what to improve in order to get better.

So this brings me to the issue. What makes–up a great study envi­ron­ment? Although I’m usu­ally not get­ting much com­ments here on the blog (an under­state­ment!), I’m now hop­ing for you read­ers to enlighten me a bit and send me your own thoughts on this issue.

To start with, I’ll share some of my own ideas about what is important.

Straight and infor­mal com­mu­ni­ca­tion between stu­dents and staff. We (lec­tur­ers, pro­fes­sors etc) should meet stu­dents face to face, talk to them and treat them with respect. In Swe­den, there are very few vis­i­ble signs of hier­ar­chy at uni­ver­si­ties. We don’t use titles, and stu­dents and staff can meet and talk on equal terms. I think it’s very impor­tant that stu­dents feel that they can talk to me and ask me ques­tions when they don’t under­stand. I also hope to reach a point where they feel that they can talk to me in con­fi­dence about things that are not so good.

Cre­at­ing a sense of pur­pose. Most engi­neer­ing stu­dents care less about money and more about feel­ing that there is a sense of pur­pose in what they do. They’re quite ordi­nary peo­ple who wants to feel that they make progress, make a con­tri­bu­tion, and can expect rea­son­able pay when they grad­u­ate. But isn’t it impor­tant that we as staff are able to com­mu­ni­cate that there is a mean­ing in spend­ing the time and effort needed to get the grade? I myself find it very dif­fi­cult to learn some­thing that I don’t get per­son­ally involved with. On the other hand, some­thing that oth­ers’ con­sider to be dif­fi­cult can be easy for me if I only feel that I want to dive into it. Are you like that too?

Cre­at­ing a sense of pride and pres­tige. Yes, I think it’s impor­tant that stu­dents feel proud of their uni­ver­sity. They want to be able to tell their friends that they made a good choice, that the edu­ca­tion they chose will give them a great job when that day comes. They want to feel that they made the right choice and that they can get some pres­tige out of that choice.

Updated and attrac­tive lit­er­a­ture. I’ve seen too many exam­ples where the lit­er­a­ture on higher courses is made–up of old type­writer writ­ten com­pendi­ums from the 1970’s. To me, that sig­nals that this is a course where nobody both­ered to write any­thing new in the last thirty years. Stag­na­tion. This effec­tively erodes any poten­tial sense of pride and pres­tige that we man­aged to develop.

I’ll stop there, and I hope that you, dear reader, feel that you want to share your own expe­ri­ences on what makes an edu­ca­tion good or truly excel­lent. Do you think I’m right in what I write above? What more is impor­tant? Give it a shot, please!

Ash cloud: Societal and economical consequences of extended flight ban

Today’s soci­ety depends on flight for sup­ply and deliv­ery of goods. An extended flight ban has severe con­se­quences. Here are some examples.

Med­i­cines: Ten per­cent of Swedish drug import is by air­borne freight. Short­ages may occur after another few days. Backup plan is to import by car from cen­tral Europe, says one major sup­plier of med­i­c­i­nal prod­ucts. [source]

Man­u­fac­tur­ing: Indus­tries will prob­a­bly suf­fer from starved sup­plies within a few days. In Swe­den, the daily value of export cor­po­rate flight freight is esti­mated to 500 mil­lion Swedish kro­nor (SEK), approx­i­mately 50 mil­lion Euro. Approx­i­mately the same value is imported on a daily basis. [source]

Trans­plant organs: Before 9/11 organs were handed over to air­craft crew in last minute before take off. The crew brought it in the cabin or even in the cock­pit. Nowa­days, most trans­plant organs are trans­ported on reg­u­lar flights and hand held by couri­ers with reg­u­lar tick­ets. [source]

Flight: The con­se­quences for air­lin­ers will be severe. Gov­ern­men­tal inter­ven­tion may become nec­es­sary.  Stock­holm Arlanda air­port (ARN) is now closed for the first time since its inau­gu­ra­tion in 1960. [source]

Flight freight: The con­se­quences can be severe for the flight freight indus­try, which is just about to recover from the recent reces­sion. As an exam­ple, flight freight makes up 25 per­cent of all British imports by value, but just 0.5 per­cent of all imports by weight. Most imports go by reg­u­lar flights: 70 per­cent of the air freight that comes into the UK is car­ried in the bag­gage hold of pas­sen­ger air­craft. [source]

Reg­u­lar post: Longer deliv­er­ies can be expected. 27 per­cent of Swedish post is by air freight. [source]

Per­ish­able prod­ucts: Exotic fruits, roses, aspara­gus, grapes, green onions, let­tuce, pineap­ple, baby sweet­corn, orchids and pre-packed fruit sal­ads are exam­ples of goods that may be lack­ing in a cou­ple of days. [source]

Super­mar­kets: Not only indus­try is oper­at­ing accord­ing to just–in–time prin­ci­ples. Mod­ern super­mar­kets are too.Selected short­ages may occur i a few days, mainly regard­ing items like fruit, veg­eta­bles and flow­ers. High–tech items like the Apple iPad can also be affected. [source]

Tourism: Uncount­able tourists are stuck on air­ports and hotels all over the world. Hotels are full, trains are full, no rental cars avail­able. Swedish tourists arrive to south­ern Europe and are then forced travel home from e.g. Italy, Greece, and Spain by bus, a 24 to 48 hour trip that is a pain for infants and elderly. [source]

How­ever, accord­ing to Ice­News there are signs that the erup­tion at Eyjaf­jal­la­jökull is com­ing to an end. If (when) the flight ban ends, there will be a cou­ple of days before flight sched­ules return to nor­mal again.

Is this volcanic ash?

I made an exper­i­ment and placed a white plate out­doors on my veranda this after­noon. Dur­ing this time there was a light rain shower. When I checked the plate about an hour later, I found a num­ber of small par­ti­cles, seen in the pic­ture below.

I’m uncer­tain of how much debris that would nor­mally come with the rain, but the amount of par­ti­cles is rel­a­tively large, and I sus­pect that these are ash par­ti­cles from the Eyjaf­jal­la­jökull vol­cano. I live on the out­skirts of a small city where air is fresh and unpol­luted. I may be wrong, but that’s what I think…

Update 18 April: I read that the Nor­we­gian Mete­o­rol­o­gisk insti­tutt has also col­lected rain water (DN). Pho­tos from an exper­i­ment sim­i­lar to mine are shown at YR.no. When analysed they found that the col­lected dust con­tained small frag­mem­nts that look like glass. Dur­ing explo­sive erup­tions like at Eyjaf­jal­la­jökull, magma (molten rock) boils and forms bub­bles like soap bub­bles. These bub­bles explode and small frag­ments that look like small pieces of glass with rounded cor­ners, spread with the wind.

Beautiful pictures from Eyjafjallajökull volcano

The vol­canic erup­tion on Ice­land is caus­ing seri­ous trou­ble, both for indi­vid­u­als and for soci­ety at large. Still, there is some­thing deeply fas­ci­nat­ing about the enor­mous pow­ers that are let loose when a vol­cano erupts.

The cur­rent erup­tion at Eyjaf­jal­la­jökull started on March 20 at Fim­mvörðuháls, which is located between Eyjaf­jal­la­jökull and Mýrdal­sjökull. The ice cap of Mýrdal­sjökull cov­ers the much big­ger vol­cano Katla, which his­tor­i­cally has fol­lowed with an erup­tion every time that the Eyjaf­jal­la­jökull vol­cano has erupted.

Below are some beau­ti­ful pic­tures taken by pho­tog­ra­phers vis­it­ing the site of the first eruption.

Heat–haze above lava flow at Eyjaf­jal­la­jökull on 28 March 2010. Click to enlarge. (Bruce McAdam/CC BY-SA)

Tourists at the vol­cano on 28 March 2010. Click to enlarge. (Bruce McAdam/CC BY-SA)

Ice­landic pho­tog­ra­pher Örvar Atli Þorgeirs­son wit­nessed how mas­sive amounts of steam was gen­er­ated, writ­ing that:

The lava from the erup­tion flows into two steep and deep canyons, Hrunagil and Hvan­nárgil. Here lava is flow­ing into the longer Hvan­nárgil just an hour after it going down the canyon.
The upper part of the canyon was filled with deep snow and ice. When the 1000°C hot lava mass and the snow/ice come into con­tact huge clouds of steam are formed. Occa­sional explo­sions also occur as steam gets trapped under hard­ened lava.

His amaz­ing photo of the event is seen below.

Steam is gen­er­ated when lava meets ice and snow on March 31 2010. Click to enlarge. (Örvar Atli Þorgeirs­son/CC BY-NC-ND)

Erup­tion at Fim­mvörðuháls on April 3 2010. Click to enlarge. (Ulrich Latzen­hofer/CC BY-SA)

Sev­eral other great pho­tos are found here.

Ash cloud over Europe

Pre­dicted ash cloud dis­tri­b­u­tion for Sun­day 18 April at 06h00 GMT+1. Source: Mete­o­rol­o­gisk insti­tutt, met.no.

The above dis­per­sion map, which is a sim­u­la­tion, shows that the ash cloud from the Eyjaf­jal­la­jökull vol­cano is likely to remain over Europe for at least another cou­ple of days. As seen in the pic­ture, the cloud is expected to widen and remain over parts of Scan­di­navia and cen­tral Europe as of Sun­day 06h00 GMT+1.

Swedish media is report­ing that some air­ports in north­ern Swe­den may open today (SvD, DN). But my inter­pre­ta­tion of the map above is that those are excep­tions, until sun­day at least.

Update 17 April: Accord­ing to Swedish media, the ash cloud will remain over Europe and Scan­di­navia for sev­eral days. Check out my vol­canic ash plate–experiment.

We said “Send cash”, not ash…; How will extended flight stop influence society?

Satel­lite image shows ash cloud from Eyjaf­jal­la­jökull vol­cano stretch­ing towards cen­tral Europe. Image by NASA God­dard Space Flight Cen­ter (Flickr) on April 15 2010.

It’s fas­ci­nat­ing to think of the con­se­quences if the ash cloud from the erup­tion of Ice­landic vol­cano Eyjaf­jal­la­jökull con­tin­ues to shadow Europe for a longer period of time. The above pic­ture shows how the ash cloud, clearly vis­i­ble, stretches from Ice­land across the Atlantic beyond the Faroe islands and Shet­land islands towards cen­tral Europe.

Cur­rently, media and author­i­ties talk about the flight stop con­tin­u­ing for tomor­row Fri­day (SvD, DN). But the erup­tion could last for a long time, and if it does, it will be hard to esti­mate the con­se­quences. How depen­dent is mod­ern soci­ety on flight? I don’t know, but I sus­pect that the eco­nomic costs of an extended stop would be enor­mous. Can it lead to short­age of the exotic foods that we’ve learned to take for granted? A short­age of lemon grass at the super­mar­ket within a few days is no dis­as­ter, but how much more of what we eat on a daily basis is deliv­ered by flight, really? Fresh fruit I sus­pect. What more?

I’m read­ing that Swedish for­eign min­is­ter Carl Bildt sus­pects that the Ice­landic are bring­ing in the old Norse gods to help sort­ing out the finan­cial crisis…

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What are strategic capabilities?

The con­cept of capa­bil­i­ties in strate­gic man­age­ment is appeal­ing because it sug­gests that a company’s com­pet­i­tive­ness depends on how it does what it does, not only what mar­ket it is in. To me and most oth­ers with an engi­neer­ing back­ground this is totally obvi­ous. Any the­ory that sug­gests oth­er­wise seems highly implau­si­ble and is also rejected by numer­ous exam­ples of com­pa­nies with strong and unique engi­neer­ing skills that man­age to cre­ate a mar­ket for them­selves based on their own capabilities.

That is not to say that choice of mar­ket is unim­por­tant, but a bril­liant plan can eas­ily be ruined if the nec­es­sary capa­bil­i­ties are lack­ing. Sim­i­larly, a plan which may appear mediocre on paper may become highly suc­cess­ful if con­ducted by a team with excel­lent capa­bil­i­ties. Oper­a­tions mat­ter, and devel­op­ing capa­bil­i­ties that make oper­a­tions suc­cess­ful is a highly strate­gic issue.

A key ele­ment of the capa­bil­i­ties frame­work is iden­ti­fi­ca­tion of the foun­da­tions on which dis­tinc­tive and difficult–to–replicate advan­tages can be built, main­tained and enhanced (Teece et al. 1997). To my sat­is­fac­tion, the cited authors also found that “The bal­ance sheet is a poor shadow of a firm’s dis­tinc­tive com­pe­tences.” Instead, it is nec­es­sary to develop capa­bil­i­ties that help the com­pany to cre­ate com­pet­i­tive advan­tage. This process takes time, and unique and deeply rooted capa­bil­i­ties can­not be bought off–the–shelf.

I would like to offer the fol­low­ing definitions:

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Process flexibility in steel plants

This post is an edited excerpt from my the­sis “Strate­gic and oper­a­tional capa­bil­i­ties in steel pro­duc­tion”. You can down­load a full PDF here.

Capa­bil­i­ties that fol­low from flex­i­bil­ity on the machine level become more impor­tant when a steel plant is pro­duc­ing a wide prod­uct range and pro­duc­tion vol­umes are low for each vari­ant. Setup costs increase, and so does the amount of WIP and gen­eral com­plex­ity of operations.

Flex­i­bil­ity is a char­ac­ter­is­tic of the inter­face between a sys­tem and its envi­ron­ment that can be seen as “an absorber for uncer­tainty”. It has a buffer­ing func­tion, as for exam­ple vol­ume  flex­i­bil­ity that allows pro­duc­tion to adapt to vari­a­tions in demand.

Process flex­i­bil­ity yields the capa­bil­ity to process an arbi­trary sequence of prod­ucts with min­i­mum time and cost penalty. It pro­vides the abil­ity to change quickly among a group of known prod­ucts, and to move quickly, smoothly and cheaply from one state to another with­out great cost and/or organ­i­sa­tional disruption.

Hence, flex­i­bil­ity serves as a “buffer against vari­abil­ity” by increas­ing the short–term abil­ity to process an unplanned sequence or com­bi­na­tion of products.

The degree of process flex­i­bil­ity depends on both avail­able tech­nol­ogy, the poli­cies that guide its oper­a­tion, and the pres­ence of organ­i­sa­tional capa­bil­i­ties needed to realise the desired poli­cies. For exam­ple, pro­fi­ciency in Shingo’s SMED method pro­vides a sys­tem­atic approach to increase process flex­i­bil­ity in production.

How does process flex­i­bil­ity help to improve pro­duc­tiv­ity? It elim­i­nates the need for buffer­ing with inven­tory. In the con­text of steel pro­duc­tion, process flex­i­bil­ity deter­mines (at any given time) the capability

• of the melt­shop to pro­duce a par­tic­u­lar steel grade;
• of the con­tin­u­ous caster to cast a par­tic­u­lar steel grade and slab geom­e­try; and
• of the hot strip mill to roll a slab of a par­tic­u­lar grade, width and thick­ness into the desired tar­get thickness.

Dif­fer­ent com­pa­nies must make their own pri­ori­ti­sa­tions regard­ing what tech­no­log­i­cal and work related changes to imple­ment in order to improve process flex­i­bil­ity. I will return to this sub­ject in a com­ing post.

TV">Japanese iron and sword making on Swedish TV

Those of you who read Swedish may have seen that there is a page on my blog called “Svär­dens mästare”, which trans­lates to “Mas­ter of the swords” in Eng­lish. I trans­ferred this page with­out fur­ther ado from my pre­vi­ous web site and have yet not taken the time to trans­late and rework it. The page is a brief account of an event at the National museum of sci­ence and tech­nol­ogy in Stock­holm in 2005 where Swedish and Japan­ese met­al­lur­gists, sword­smiths and oth­ers par­tic­i­pated. Myself I was respon­si­ble for the con­struc­tion and oper­a­tion of a shaft fur­nace rep­re­sen­ta­tive of pre–industrial iron making.

Iron­mak­ing at the National museum of sci­ence and tech­nol­ogy in Stock­holm in 2005. I’m seen to the right hold­ing the hammer.

It was there­fore with great inter­est that I watched the show “Secrets of the samu­rai sword” on Swedish TV (“kun­skap­skanalen”) yes­ter­day. The pro­gram, which can be viewed online at SVT Play until May 3 2010, fea­tured iron mak­ing in a tatara fur­nace, forg­ing, sharp­en­ing and pol­ish­ing of a samu­rai sword, and dis­cus­sion of the samu­rai swords’ capa­bil­i­ties in itself and in com­par­i­son with medieval Euro­pean swords.

This was almost exactly the struc­ture of our event at the museum. I was even start­ing to sus­pect that the pro­ducer of the TV show was at the museum back in 2005 or read my report from the event.

Con­trary to what many believe, Euro­pean swords were far from heavy unso­phis­ti­cated steel rods swung by brute force. Back at the museum I saw with my own eyes how real, sharp, Euro­pean and Japan­ese swords were equally effec­tive at cut­ting the spe­cial rolled straw mats that Japan­ese mar­tial arts spe­cial­ists use as sub­sti­tute for human limbs when they prac­tice. This was also demon­strated in the TV show.

One point that the show failed to empha­sise cor­rectly is that both Japan­ese and Euro­pean swords were devel­oped to serve opti­mally in their con­text. Whereas the Japan­ese swords with their sweep­ing cut­ting blows were highly effi­cient when fac­ing a lightly armoured enemy, they would have been quite use­less when fac­ing the heav­ier armours that devel­oped in Europe.

Swords are fas­ci­nat­ing, and so is the process of mak­ing them. That includes the craft of mak­ing the actual iron and steel that they are made of.