More desperate new-routing further downstream unearthed (literally) more rubbish routes. However, some of the routes above the trees are quite clean and might stay so for more than 10 minutes.

From the campsite, continue downstream from Riverbank Area for five minutes. Cross the stream at a very wobbly DIY bridge (a single log chained across two boulders - safer to take your shoes and socks off and paddle across) and head downstream a few metres to a clearing in the woods on the right. This is in front of the jumble of debris between Akamanma and Bridget.
Alternatively, on your way to the campsite, you can park at the clearing before the last fork in the road. Walk up the road to the campsite for 20m to where the Shakunage Hiking Course begins. Follow the path left into the woods for 400m or so (keep your eyes peeled for the top of the crag on the opposite bank of the stream) to a cairn and the log bridge.

Routes are described from right to left, down to up, beginning with the section right of the jumble of debris.
Bear in mind I've only done a handful of these so far.
There is an excellent pool halfway between Riverbank and Streamside, and 50m downstream from the log bridge an inspiring cypress grows out over a short wall in the right bank and a natural pool.

Hoshizuna - Starsand	5.11a*	10m
A diagonal line across the lower right slab. Good moves but poor rock.
Start on the slope below left of a bottomless corner. Step onto the slab and go up to the start of the corner. Pull right onto the slab follow the bolts across the slab (at the third bolt, you can go up then right, or right then up) to the arete. Lower off.

Sophia	5.10c	8m
The grotty short corner.
Start as for Hoshizuna, but head straight up the corner to a lower-off on the left.

Akamanma	5.12a**	8m
The steep slab left of the corner. Chipped but interesting.
Start in the centre of the slab and make neat, technical moves till it possible to reach a downward-pointing spike. A steep pull leads to the lower-off of Sophia. Overgraded.

WAKAI - Young	5.10c	8m
The short slab just right of the arete.
Start on the terrace left of the arete. Belay advised. Step onto the slab and follow the bolts to a lower-off.

Francine no Bai - In Francine's Case	5.10d*	10m
The steep line up the centre of the face to the right.
Start on the terrace after pulling round from WAKAI. Follow the obvious line to the last bolt, then head right to the lower-off on Suzume no Teppou.

Suzume no Teppou - Short-awn Foxtail	5.11b*	10m
The steep, stepped line right again.
Climb direct to the lower-off. Strenuous.

Bridget	5.8	8m
The short slab just left of the debris.
Pull onto the undercut slab using a boulder. Continue on big holds to a lower-off.

Marilyn	5.9	8m
The short inset slab 10m left again.
Climb the slab past a break to a lower-off.

Matsumushisou - Pincushion Flower	5.11a	7m
Serious barrel-scraping up the steep choss left again.
Climb the leaning slim wall past two-bolts to a lower-off.

Tokisou - Ibis Orchid	5.10c	12m
Nope, they still haven't reached the bottom.
Climb the grotty corner just left of Matsumushisou.

Sagisou - Fringed Orchid	5.11c	8m
The longer arete to the left. Slightly more solid, but...
Climb the arete. Apparently you're not allowed to step onto the ledge on the left. Possibly because it will fall down if you do.

If you (a) climbed and (b) enjoyed the last few routes, head left and scramble up round the other side of the ridge to meet Back Streamside Area. Otherwise...

Ikkyuu Soujishi e no Michi - How to be a Grade One Route Cleaner	5.10a*	15m
Makes you wonder. The left edge of the upper tier.
Step off the left edge of the terrace (onto the rock). Follow the bolts up and diagonally right to a lower-off.

Reppuu - Storm Winds	5.12c*	13m
The next line in.
Follow the bolts to the same lower-off - very technical and devious.

Hototogisu - Lesser Cuckoo	5.12b*	13m
The next line in.
Climb direct to the same lower-off. Difficult and sustained after the third bolt.

Miyako Wasure - Japanese Aster	5.12a**	17m
Another direct line to the right.
Climb direct to a lower-off. Reachy and sustained after the second bolt. The first ascent description said something about not using an obvious hold on the right. What's all that about?

Love or Nothin'	5.10a**	18m
Another direct line right again.
Climb direct between twin not-quite-cracks to a lower-off.

Uguisu Kagura - Lonicera Ramosissima	5.12a*	16m
Another direct line right again, also up a face between vague twin cracks.
Climb direct between the vague cracks to a lower-off. You're not allowed to touch either crack. According to the first ascent description.

Pit Touch	5.10c*	13m
The next line to the right.
Start below and left of a flake/overlap. Climb diagonally right up to the overlap on good holds. Pull over and cross some choss to a thin face (crux). Continue up and left to a lower-off.

XXX	5.11a*	14m
The next line to the right.
Start a couple of metres left of the arete. Climb direct to the right edge of the overlap of Pit Touch. Pull right to the arete and finish up Audrey.

Audrey	5.10b*	14m
The right arete of the main face.
Make a tricky pull into a groove in the arete. Continue easily over blocky ground, then pull left onto a short crunchy slab. A scary move up this leads to a lower-off.

Ingrid	5.10c*	13m
The protruding undercut rib to the right.
Climb the narrow rib to a ledge. Use a good crack to pull up the bulging face above to a lower-off.

Marlene	5.10b	13m
The parallel line to the right. A dangerous route.
Start in a recess. Pull up to easy ground then pull over a bulge using a flake on the left and/or tottering crack on the right to a lower-off. Take great care not to knock anything down.

Mamako no Shirinugui - Polygonum Senticosum	5.9	7m
The grotty short slab. Another poor route.
Climb the slab direct then rightwards to a blue chain below a dead tree stump. Lower off. Undergraded at 5.8 in the Japanese topo.

The line to the right is not claimed yet. From here, a fixed rope zigzags up to a small bay below a brown face. Be very careful if you use this rope. The bottom section looks OK (i.e. securely anchored), but the top section is a joke. People who leave this sort of gear in place should be neutered.

Grace	5.10c	14m
A poor route up the face left of the grotty corner in the arete.
Start at a yellow chain below an attractive crack. Step left round the arete onto grot and move up and left to a bulge guarding a clean slab. Pass the bulge on its left, make a thin pull up the face then swing right and mantel to the lower-off of Let Me See. It says here "If you stick to the line of the bolts, it's 11b."

Let Me See	5.11a**	14m
The slab and obvious crack. A very good route.
Start at the yellow chain and climb direct with a stiff move to gain the obvious crack. The crack proves to be harder than it looks. Continue to a lower-off. Worth an extra star if the approach is ever sorted out.

Tori no Endou - Bush Vetch	5.12a**	18m
Another good route!
Climb the slabby face direct. Very sustained till the third clip.

Suzume no Endou - Hairy Tare	5.11b*	16m
Not bad, either.
Start up the wide crack at the back of the bay. Layback the crack to a tricky final face. Continue to a lower-off.

Sen no Kaze ni Natte - I am a Thousand Winds that Blow	5.10d*	18m
Another decent route, but the bottom slab is already dirty.
Climb diagonally left across the little slab at the back of the bay to a ledge. Finish quickly up the steep arete above. Lower off.