Bob Lavelle

I live in Japan too. In my area at least once a week there is a lot of green garden waste thrown out, eg. tree cuttings, grass clippings etc. Perhaps you could collect them. Although, maybe not strictly legal as rubbish becomes property of the city once it hits the gomi  station ( i.e. trash collection area). You could then compost it or chip it if it's too big. Which area are you in?

As far as I've been told they can have it come out of the combine at any length.  They want me to come and meet them and tell them what size I'd like  them to cut it.  They normally cut it short and leave it in the field as it's a "waste" product. I'll probably get a variety of lengths.
Because  I can have any length I like, naturally I'd rather know before hand and save myself extra work and expense in the future.
As for plaster, yes smaller is better I've heard, under an inch is better for rough.
For topcoat one good thing about Japan is that clay and lime plasterer are still quite common, so I can buy clay plasters, lime plasters, whatever I need relatively easily.
Hopefully someone with experience whill chime in sometime soon and educate me in the finer points..

Thanks for the reply. Longer may result in stronger walls than short. But how much difference and what is "long", or short for that matter. I just can't seem to find any sites that have actually tested different lengths. What would be optimum length?
As for r values, I think you could get similar r values with long or short. Probably with short you would have to be careful about over doing the compression. Shorter  straw would probably compress easier than long.  But this is all conjecture.

I know that for plasters short is better so I want some short for that.

My main dilemma is that once I receive the straw, that's pretty much how I'll have to use it as most of the labour will be me alone so I can't afford to be spending time chopping it if I ask for the wrong length. And of course I can't uncut the straw.

On this site  
http://endeavourcentre.org/2016/04/light-clay-straw-insulation/  
they say "chopped straw, ideally 1-6 inches"

On this site http://mudstrawlove.com/natural-building-101/
They say "long".
Unfortunately I won't have time to do any tests until after delivery.
I'm finding similar advocates for both on other sites too. Hmm, what to do...

I'm going  to be renovating an old house in Japan. I want to add extra insulation using strawclay infill  for the external walls, and probably internal too.  However, I don't know how long the straw should be.  I keep finding different sites have different advice, some say long, some short.

I assume short will be easier to work with, and coat with clay, especially if I use mechanical means, i.e. some kind of tumbler, rather than tossing with a pitchfork.

I would also assume that long would create a stronger wall as the fibers would interlock more.

I'm getting the rice straw free from an acquaintance. But, harvest time is very soon so I need to tell them what I want.Their mini combine harvester can cut the straw to various lengths.  Is there much difference between long and short. As I'll probably have a lot, would long or short be more useful for other construction purposes, that I haven't thought of? What would be the ideal length for rice straw? Thanks in advance everyone.