The Shomyo Waterfall (Shomyo-daki [称名滝]; Shomyo Great Falls or just Shomyo Falls) and Hannoki Waterfall (Hannoki-no-taki [榛の木の滝]; Hannoki Falls) comprised the twin towers of waterfalls in the Japan Alps. Shomyo Daki (pictured above on the left) was said to be Japan's tallest permanent waterfall. Hannoki-no-taki (pictured above on the right) was said to be Japan's tallest waterfall though it was said to be seasonal as it would disappear rapidly when the snowpack was mostly depleted. From a statistics standpoint, Shomyo-daki was commonly quoted as having a cumulative height of 350m. Yet from the photo at the top of this page, you can also visually see that Hannoki-no-taki was even taller than Shomyo-daki.
Our experience with Shomyo Waterfall and Hannoki Waterfall almost resulted in utter disappointment due to nasty weather. Of course Julie and I have learned over the years of waterfalling that tall waterfalls in general tended to be more exposed to the whims of the fickle mountainous weather where we had to sweat the issue of clouds blocking the views. And in our case, we visited on a day where we started the 30- to 45-minute walk under some pouring rain and low clouds!
Yet despite the drenching that we took, I was glad that we pushed forward (as bleak as it looked at the outset) from the bus stop, because by some minor miracle, the waterfall deities smiled upon us as the nasty weather seemed to relent right at the Shomyo Bridge in front of the waterfalls! In fact, as we lingered here (trying real hard to do this without missing the next bus departure back to the Tateyama train station), the weather seemed to start clearing up. When the reality had set in that we had to leave or else wait over another hour for the next bus (and possibly longer given the train schedule we were coordinating this with), we had no choice but to run as fast as we could back to the bus that was about to leave.
When we were lingering at the falls, we went beyond the Shomyo Bridge, where there was a couple of flights of steps leading to a shelter and a couple more overlooks. From this vantage point, we were able to see more of the Shomyo Waterfall, but the Hannoki Waterfall started to hide itself within its grooved watercourse on the facing mountain. By the way, that shelter was what allowed us to linger for as long as we did to wait out the remainder of the downpour we were experiencing.
Anyways, from looking at how thin the Hannoki-no-taki was, Julie and I could tell that really depended on snowmelt as well as the brief but dense rainy season of early to mid Summer. As you get into Autumn (which I thought would be an excellent time to go waterfalling in Japan as well as just about all of Asia for that matter), I believe this waterfall tended to diminish rapidly, which might be why it didn't quite get the same love as Shomyo-daki.
I would put this twin tower pairing of waterfalls (not the only waterfall pairing in the country, by the way; see Ginga and Ryusei Falls) right up there amongst Asia's very best. However, the amount of man-modifications done immediately downstream of the falls kind of spoiled things a bit. That said, logging and hydroelectricity along with tourism and fishing drive the economy of the Toyama-ken ("ken" means prefecture). So, I guess having this waterfall was much better than have it sacrificed altogether!
Another thing worth mentioning was that if you're up for it (and you're willing to somehow figure out how to forward your luggage, which we didn't bother doing), the Shomyo Waterfall and Hannoki Waterfall combo was actually a side trip to the well-publicized Kurobe-Tateyama Transalpine Route through the heart of the Japan Alps spanning both the Nagano and Toyama Prefectures en route. This alpine crossing involved a combination of funiculars, walks, and bus rides while taking in mountains, lakes, a big hydro scheme, and plenty of vistas.
As you can see from the crummy weather that we faced, we didn't do it. Anyways, had we done it, there was a separate walkway that linked one of the stops higher up the mountain to these waterfalls directly. And from there, we could have taken the bus back to Tateyama Station to complete the alpine traverse.
Directions: Since getting to the Shomyo Waterfall and Hannoki Waterfall combo requires a bit of logistics, we'll break down the hectic day we had where we managed to bypass the Transalpine Route and still get to see the falls before ending the day in Toyama. On the return train ride back to Toyama from the waterfalls, we nearly missed a local train connection, which would've stranded us elsewhere, but that's another story.
Anyways, the timeline of our day involving these waterfalls is shown in the ordered list below:
Left Matsumoto (or Matsumotooooh Matsumotooooh Matsumotooooh) and caught train for Nagano (some time not long after 6am)
Caught Naoetsu line at 8:12
Caught JR shinkansen train making a stop in Toyama at 10:10
Dropped luggage at a Toyama accommodation at 11:35
Caught non-JR local train for Tateyama (1190円 each way) at 12:19
Caught bus to Shomyo-daki at 14:00
Caught bus back to Tateyama Station at 15:25
Caught train back to Toyama Station with a connection (that we nearly missed) at 15:50