Hello 10 colors tenkara community, I came across this video a few days ago and thought I’d share a little of what I have learned about this ancient art form.
Over the past 7 months or so I have been studying the art of Edo Wazao under the tutelage of Masayuki Yamano-sensei. About two weeks ago I traveled to his shop to work on my five piece tenkara rod we are building together. During the visit we discussed urushi. My rod is getting to the point in its construction where we should apply the urushi lacquer. However, since I have a 3 month old son (named Tadashi) and urushi causes horrible reactions we decided to use a synthetic lacquer instead. Apparently some people are so sensitive to urushi that if they are in the same room as the lacquer they have a skin reaction similar to poison ivy. Families in Japan that specialize in urushi expose their infant children to it in very small doses over a period of many years, so that when they are full grown they are immune to it and can safely carry on the family business.
While urushi does require some special handling if a bamboo rod is finished using it you can temper and re-straighten the rod for hundreds of years. If you use synthetic lacquer the rod will burn where the female ends are wrapped in thread (for reinforcement prior to drilling) when you temper and re-straighten. Also, the finish will only last three to four decades.
While I’m a little bummed to not be able to build a rod that will last hundreds of years I’d rather not have Tadashi contract a full body poison ivy rash from me (not to mention all the people I’d sit next to on the train on the way home…).
Last month I harvested some live bamboo and did the initial tempering to remove the sap. In 8-10 years once the bamboo has cured and hardened I plan to return with Tadashi and commission a rod from Masayuki Yamano-sensei for Tadashi using the bamboo that I harvested way back in 2017! Since Yamano-sensei will be building it this one will be finished with urushi. While I’m there I’ll probably have Yamano-sensei temper and restraighten my rod. I’m sure it will need it by then 
what an amazing experience it must be