ANSWER























           
This is called “Kokuban-keshi cleaner” and used to remove chalk dust from Kokuban-keshi which I hold. You slide them on it and a vacuum inside inholes the dust.　But it is naturally expected that you ask a very simple question:”Why do you use it?  It’s enough only to beat two kokuban-keshi against each other and put out the dust”. I have two opinions to answer the question.














           First of all, it has some risks: students’ dislike against this choking smoke, injuring our lungs, a possible cause of tuberculosis etc, so that this cleaner seems to be getting more & more popular. However, there is complaint about even using a blackboard, and also suggestion to use a whiteboard or a newly invented board using the latest technology instead, but there is also some problems. For instance, these items are a little too fragile to set in an environment, where a lot of children run around. Moreover they cost too much to introduce, so blackboards will still keep clinging to their position for the near future.


           Secondly, Japanese tends to cherish everything, use everything efficiently, and want everything to be in the best condition. In Edo era, circa 17-19c when samurais ruled Japan, there was a perfect co-recycle system because of less resources. There were various kinds of craft workers and agencies specializing in recycling such as those who repair pans & dishes, buy old clothes & trashes, and even collect human waste. Therefore, it is natural that they want this usual item kokuban-keshi to work well.