Anyone who has fished with a tenkara rod for any length of time soon realizes that tenkara rods can break. They break much more frequently than their reeled western fly rod counterparts. This tendency to break can be frustrating and if done repeatedly, be downright expensive.
Most tenkara rods break due to operator error. Some common ones are breaking the tip section when attaching a line or collapsing the rod. Another classic is pulling back forcefully or whipping the rod when the fly gets snagged. Without question, errors such as these have a high chance of breaking one of the rod segments.
It has been said by many that "tenkara rods don't break on fish" (as long as the tippet is weak enough to break before the rod). But there are many anglers out there that would disagree. Unfortunately, tenkara rods can break on a fish, such as when setting the hook or playing the fish. It does (or shouldn't) happen often, but it does happen.
Of course, another cause of rod breakage is material or design flaws. In general, I think this is rare but it too does happen.
The Nissin Pro Spec 2-Way 360 7:3 is a rod that has a reputation for breaking. Mine broke three times, each time at the third section from the lilian (in the Japanese numbering convention, the tip section is number one). One of the breaks was my fault, on a snag. But the other two were on (smallish) fish, when setting the hook. All three times the third section broke at exactly the same place, near the joint between the third and fourth sections. I have heard many other owners of the Pro Spec 2-Way 360 7:3 complain of breakage in the exact same spot on the rod. This has me thinking that it has to be form of materials or design flaw.
I had one of the original Pro Spec 2-Way 360 7:3 rods from when they were first released by Usaki-Nissin. Maybe the rod has since been strengthened or modified, but back then I was tired of buying new third sections so I decided to do a workaround.
At the time I had some sections of another rod lying around. That rod was the AllFishingBuy Hirame -ML-3909. This Nissin counterfeit rod is made in China for AllFishingBuy, a strangely named fishing retailer on Staten Island. I bought the rod in 2012, and although it's not a super high quality rod, it has served me well over the years and has been remarkably robust. Of the original tenkara rods that I bought in 2012, it is the only one I never sold. It's been a great back up rod. I have caught some nice sized trout in high gradient streams with it and it never has broken.
I had the top three sections for the Hirame as well as other rod parts in my supplies, so on a whim I tried them on the Pro Spec. It turned out that the third section the Hirame mated perfectly with the fourth segment of the Pro Spec. Unfortunately, the Pro Spec's second section didn't mate with the Hirame's third segment so I had to use the top three segments of the Hirame.
I was concerned at first that since the two rods had totally different tapers that it wouldn't work well and might even break the Pro Spec's fourth segment. But as it turned out, the workaround worked perfectly! The rod had nearly the same action and the rod curve under load was a perfect, smooth arc. The addition that the Hirame's sections are very inexpensive didn't hurt either!
From that point on, I never broke the Pro Spec 2-Way 360 7:3 again. The Hirame-ML-3909 top three sections were much more robust than the OEM Pro Spec sections. I fished the rod hard for a few years before selling it. It never let me down after making the change.