Smallmouth Bass Fishing at Ozuchi Dam: the Upper Yasu River in Japan
On October 2, 2024, I took a short break from work to visit Ozuchi Dam, located in the upper reaches of Yasu River in Shiga Prefecture, Japan. The dam is about an hour's drive from our office, making it one of my most frequent fishing spots.
As you can see from the photos, Ozuchi Dam has a unique drainage structure, which has made it somewhat famous among Japanese dam enthusiasts. However, as a fishing spot, especially for bass fishing, it remains almost entirely unknown. Very few anglers are aware of this location, and it’s hard to find fishing information about it online. I’m one of the few local anglers who regularly fish here.
The Best Spot: The Backwater
While smallmouth bass can be caught on the main lake side of the dam, the best fishing spot is the backwater that feeds into the dam. Since Ozuchi Dam is relatively small, the backwater isn’t very large either, but it’s home to many big smallmouth bass. The water is incredibly clear, allowing for easy sight fishing, which makes it an exciting spot.
Such clear water bass fishing site are rare in Japan, making this location a precious fishing ground. Additionally, because it’s not well-known, there’s little fishing pressure, and the bass are much easier to catch compared to more popular locations.
Abundant Baitfish and Hungry Bass
The backwater area is teeming with baitfish, and many black bass migrate from the dam into the backwater to feed. This makes it easier to target the bass, especially during feeding times. The primary prey for the smallmouth bass in this area are species like sweetfish (Ayu) and dace (Ugui), as well as shrimp, which are abundant in the waters. You’ll often see bass chasing and boiling the surface as they hunt for prey.
Effective Tackle for Ozuchi Dam
When fishing this spot, I primarily use a free rig with 14-pound line and baitcasting tackle. My reel of choice is the Shimano 16 Metanium MGL, a versatile baitcasting reel that handles both light and heavy lures with ease. Its versatility is why I use it in most situations here.
For sight fishing, I use a bait finesse tackle with a 6-pound line, equipped with a Shimano 16 Aldebaran BFS XG. Although a spinning tackle could also work, I prefer baitcasting for its casting accuracy and better lure control.
Line Selection and Technique
The choice of line is particularly crucial in this clear water. When I cast the same lure with both the 14-pound and 6-pound lines, the bass’s reactions are noticeably different. Thinner lines are not only less visible but also allow the lure to move more naturally in the water. Additionally, bass in this area tend to shy away from the sound of the line cutting through the water when I add action to the lure with rod movements. For this reason, I often rely on reel retrieves to impart action to the lure.
Best Fishing Conditions
Ozuchi Dam’s backwater truly shines after a typhoon has passed and the water levels rise. Upstream from the backwater, there are many small crabs, and when the water level increases, these crabs are washed down into the dam. The bass know this and tend to stay near the bottom, making it easier to catch them under these conditions.
Normally, the water is extremely clear, but after heavy rains, the water becomes murkier, creating ideal fishing conditions. After one such storm, I was able to catch around 20 smallmouth bass over 40 cm (16 inch) in a single half-day session.
Final Thoughts
Today, I’ve shared my experience fishing for smallmouth bass at Ozuchi Dam, a hidden gem known only to local anglers. The crystal-clear waters provide a unique fishing experience, and I often use this location to study the behavior of smallmouth bass. Since I visit this spot frequently, I’ll continue to share updates about my fishing adventures here.
Until next time, see you in the next “Fishing Report in Japan!”
