Japanese cedar.  These chopsticks are used for a meal during ochaji. 

 I found this site reasonable for those readers not familiar with Ocha or Ochaji.  http://japanese-tea-ceremony.net/

We can use both sides. 

The left is an used gift envelope that contained a new set if chopsticks.  These are shorter compared to the standard size on the left.  They are probably used in the least formal occasion.  In Ocha, we have formal, semi-formal, and the least formal presentations.  There is no casual although these terms are relative.  I might have wrote about this before and used the word casual to mean the least formal.

Bamboo.  Hosts usually buy or make new sets of green bamboo chopsticks for an Ochaji.

These are old.  

Top two are made of black bamboo, I believe.  They are longer and hard to handle.  It's all about entertaining guests even though Ocha teachers would say, "Ocha is simplicity, economy of movement and..."  Today, we don't have many skillful craft workers, so the price of all these items either shot up or replaced by machine made in foreign countries.  I haven't researched about it lately.