While the google trends report is kind of interesting to play around with I think in many ways it can be misleading. From 2009 ~ 2011 most people didn’t know much about it, and a lot of internet searching was needed. Today more people know something about it and have more opportunity to learn from someone first hand, without needing to figure it out on their own by finding information on the internet.
Probably the three best places that could answer that question are: a) manufacturers & dealers of tenkara products. And Tenkara Guiding companies. Are their sales of tenkara services, and products increasing, stagnant or decreasing? I doubt very much if any of them want to provide that information. Or b) the membership or traffic to tenkara forums, blogs, Facebook groups, twitter, etc., and c)what are the numbers of people attending tenkara gathering such as the TUSA Summit, Tenkara Jam, Midwest Tenkara Fest, etc.
Of course the gatherings listed above are only the ones in the USA. There is also the Tenkara Fest in Europe, I think in France last year. Maybe the Russians also have something similar. And the various ones I see on Japanese tenkara websites always seem to be well attended.
An additional type of website would be the various imaging sharing websites such as Instagram, Imgur, Printerest, Webshots, and many others :
https://en.wikipedia.org/wiki/List_of_image-sharing_websites
Judging solely by the increasing number of images on image sharing website that show up in the results of an internet search for tenkara related words or phrases I would say tenkara is growing. But maybe that’s just more people using those types of sites, and not an increase in the number of tenkara people, For my purposes I find them quite annoying. I find more and more of them turning up in my search results, but they are not the type of thing I am looking for.
Another are the increasing number of YouTube and Vimeo videos. And the increasing number of websites that collect tenkara videos, & attempt to file them under different topics. In my internet searches it seems I am finding more of them.
Only Michael Agneta knows the fall or rise in the number of people reading issues Tenkara Angler.
I started tenkara fishing in 2010. But have spent more time on the river tenkara fishing since 2013. In all that time I have only met by chance one guy with a tenkara rod. Only two or 3 who knew what is was. About the same number who didn’t know and asked about my tackle. It seems odd that few would ask me what kind of gear I was using as I am the only guy in sight with a rod that generally is twice as long as any other rod anyone else is using, and with no reel. I think where I live mostly people believe they are supposed to mind their own business. From that experience I see no indication that tenkara is growing.
I do get the impression that manufactures are still seeing an increasing market for tenkara gear. I think in 2016 Nissin introduced several new tenkara rods. In I think 2016 Daiwa introduced the Expert Tenkara rods and a tenkara kit. Suntech has started making the Tenkarabum rods. Shimano has just introduced two new rods and and a kit aimed at attracting western fly anglers to tenakra. Tenryu is making a limited edition tenkara rod that is pretty pricey and apparently getting orders for it.
The Discover Tenkara guys found buyers for their Karasu rod, plus they appear to have a steady interest in both their free videos and their pay to download videos and files. I doubt they would keep making them if they did not see interest. The recent loss of many of their earlier works I think is just a set back. Tom Davis recently posted a nice review of their print issue book, How to Fool Fish with Simple Flies.
Since Aug 2017 ten new tenkara products have been posted on troutnews website. But before that is was March 2017 with only six more new products posted in 2017. They appear to be posting more new items more frequently than the previous couple of years. From rods to lines, to hooks. Though of course there are new product offerings that do not get posted there. One of the more recent products is the new Tsuribito / Dr. Ishigaki DVD. From his blog post about the DVD he was hoping there would be enough interest to not loss money on it. But they appear to have sold out quickly at the Yokohama fishing show. But who can know if most of the sales were to tenkara veterans or to the newly interested.
Three Rivers now has their own rod. I see the Tenkara Rod Co. rods showing up on several Japanese websites. I think Riverworks and Tenkara Tanuki both started full time in 2016 or maybe 2015. And a few others.
Not sure what to think about what’s happening at TUSA. They haven’t introduced any new rods recently. But my bet is they don’t need too because the rod models in their line up are still selling well against new offerings from both big name companies and small ones too. They appear to update their rod models but not give then a new name. And maybe it’s just an illusion, but it seems to me that I see more people viewing their forum than I did a year ago when it seemed slower.
While I live in isolation from most other tenkara anglers. From what I can see I think interest in tenkara is still expanding based on seeing more products being introduced, especially higher priced products. I don’t think companies would make them if they did not believe they would fine buyers. The expansion of images on image sharing websites might be increased interest. Or maybe just more people wanting to do the social media thing and talk about it more, though the number of people might not be expanding as much as the number of shared images. Hard to judge what the growth rate is. Rapid or slowing, but I think it is still expanding.
Tenkara outside of Japan reminds me of the story about Drummer Hoff, I read to my son when he was little.
You remember don’t you?
Pvt Parriage brought the carriage, Corp. Farrel brought the barrel, Sgt Chowder brought the barrel, Capt Bammer brought the rammer, Capt Scott got the shot (the cannon ball), Gen Border gave the order, but Drummer Hoff fired it off.
Many people have now brought many things to tenakra, but Daniel Galhardo fired it off.
At least outside of Japan.
5¢ opinion.