I've read in several places that when you start tenkara fishing First learn to Cast. Then learn to cast accurately to the desired point. I'd add thirdly to next learn to land the fly first with out splashing line on the water and spooking the fish. That can be done with simple straight cast or cross body straight cast. Which maybe the only casting skills you need if you only fish open streams with simple current patterns.

But if you fish tighter brushy streams where you would like to be able to drop your fly under low branches where the fish are sheltering or streams with large stones that create water currents at various angles to the direction of the main current flow, where simple though perhaps excellent straight cast won't do what is needed, it might pay to spend a little time learning some more advanced tenkara casting techniques.

Rob Worthing, from Tenkara Guides, wrote a series of 3 articles over three issues of Tenkara Angler online magazine, Michael Agneta, of Troutrageous, is also the guy who edits and publishes Tenkara Angler. Michael in one blog post has collected links to all three of Rob's casting articles for convenient reading.

I admit that some of the cast are difficult to understand from just reading descriptions of them. Rod and line move in changing directions, with changing rod speeds, with changes in arm position, and hand rotation. I've not yet made much progress my self learning how to do them. Being cold and snowy outside now doesn't help to try to learn the techniques. You can read and think you understand what needs to be done to make the cast, only to find it doesn't work on first attempts. It take time and practice to move from having the know how to having the actual skill.

Anyway, here's the link to the 3 Advanced Casting Technique articles blog post, links to each article are in the blog post. If you're interested in reading them and finding out if you can learn them: