I would like to describe the leader setup I am presently using for my Tenkara nymphing. As I previously stated I first became interested in Tenkara because the equipment seemed like it would work out well for Czech nymphing. This method of fishing uses little to no fly line and employs longer than normal fly rods. As I found it very difficult to find a fly rod longer than 10' long in this country, I thought the 11'-13' Tenkara rods may be a viable solution. As it turns out they are...
The Leader Material
Though I don't feel it is necessary I decided to try the authentic level line used with these rods. The level line comes in a bright pink color which works out quite well as a sighter. It is available in two strengths 10lb and 15lb test. What I do like about this line is its stiffness which I feel helps in delivering a team of flies. I thought I may have a hinging problem because I use soft supple tippet material but the "casting" method used for Czech nymphing with Tenkara rods poses no such problem.
You will need to add a few new knots to your repertoire if you have never used this type of material or fished Tenkara before. The knot illustrated on the right is used to attach you leader to the braided section of line attached to the rod tip. This knot is extremely simple to tie. The first time you tie it you think "this will never work", but it works like a charm and you can remove it from your rod by simply pulling on the 1/2 tag end that you leave.
You will also need a new knot for attaching your tippet to the level line, though you can probably get by with out it. This tippet knot is also very easy to tie. The illustration does not show it very well but you are only leaving a 1/2 inch of tag at the base of that figure 8 knot. I played around with running droppers off the main line in this fashion but the line is too heavy/stiff for Czech nymphing (not to mention the bright pink color)
Detail of Tenkara rod tip
Leader Design
Tenkara techniques call for a leader up to a rod and a half in length. So for the 12' Yamame rod I am using, that would mean a 18' leader. That worked out to be too long for Czech nymphing. It forced you to hold the rod tip too high, effectively becoming a high sticking technique. If you high stick, then you may want to consider the longer leader. What I ended up with, was an overall leader length of 13 or 14 feet. This allowed me to fish close in and at full reach but still get my flies down. You may have to experiment with the length of level line used but basically I am running a couple feet 5x tippet to my first dropper then positioning my flies 18"-20" apart.
Looking at the illustration above your level line will end at the surface of the water or slightly below. This means you will have to play around with the length of level line and tippet based on the depth of the water. The water I fish with this method is fairly consistent in depth so I have not had to do a lot of fooling around with leaders. I have not actually measured my level line section but I believe it is no more that 6'-8' long (I'll check this and post a correction if needed). Once I worked out the details I have not had to change my leader much other than adding or subtracting tippet. Your results may vary...