A charcoal pit and a biochar stove

Here is a long series of pictures taken during a bamboo charcoal workshop held by an elder wizard during Yamauto festival 2013. The whole process is very simple and straight forward... but unfortunately it has some downsides too, in the loss of biomass, leftover ashes and possibly *very* bad emissions at some point.
Perfect opportunity to display and show my improved biochar making stove. Many people came along and were able to grasp the basic concept by watching it happen.  

 At the beginning a shallow square pit is dug out, as big as the corrugated sheet that was gathered to cover it at the end of the process. A small fire gets started in the center of the pit, using the most dry pieces first then adding whatever other pole, even the most wet ones.

As the fire grows bigger, all the humidity of the bamboo boils out in steam. Several loud sounds like gunshots happen as the bamboo sections crack open in the fire... 

We keep adding more and more bamboo, building up a quite big and hot fire. Then when every pieces is burning... we put the fire down doing the quenching by pouring various buckets of water all around the inside of the pit. 

Soon after doing the quenching we cover all the pit with the roofing sheets making sure that there is a good overlap between each piece, then sealing the whole thing with soil so that no smoke is coming out. 

So it's done! After a couple of days the heat goes down and the pit it's ready to be opened to take out the charcoal left. The soil used to seal the top could be reused (I don't know if it will though...) as well as the pit.
On the side of this ancient practice, I laid down my stove set explaining the main features and the substantial difference of approach: (1) trying to have the cleanest emissions as possible, (2) trying to reduce the ashes to zero (meaning no waste of biomass) and (3) use the energy of the process to cook or to heat water.  

My hand made Elsa-stove replica worked quite well, standing on the side of the pit attracting the interest of everybody, being obviously something completely different.

Here are some of the most keen and grateful participants of the workshop that gathered at some point maybe about 20-25 people. Thank you all for watching and putting up with my broken-japanese language and weird foreigner accent... maybe you all carry within the perfect flame of Pyrolysis!!! 

Still life with biochar: on the lower right corner the bottom of the stove is upside down, showing the hexagonal pattern that I chose to make... improving a lot since the very first test. Now getting ready for sizing it up ;)