Most (but not all) are sedimentary rock. Lots of vertical and overhanging problems. Not all of the problems in the river bed can be accessed after a lot of rain, and some will be dry season only problems. Just out of the river beds the rock has a totally different feel. There are some really nice lines just a short walk up the trail.
I have no Idea how many problems we will get out of this place. We've only just begun.
The very base looks like it has great problems but is fenced off. DON'T screw it up for every one else by going down there. You can find plenty of problems outside of the protected area.
Less than 30 min North of PNU in Busan by car. You can pick up bus 12 from in front of E-Mart by the Guseo Subway or east of the PNU subway stop. It takes you to within a short distance of the trail. You can also catch bus 88 from Hopo in Busan.
Even thought there are tons of ways to get there this is the one I know best...
From the Nopodong terminal (or many other places) you catch bus 12. It doesn't actually stop at the terminal but close enough. just walk across the street and head south until you hit the giant split the bus stop is a little stop on that split. Take it until you see the giant warehouse building out the right side of the bus. I believe the name is 삼계1일. It will be after you have gone through most of yangsan and it starts to look countryish. Or just tell / show the driver this (용주사 Yongjusa) and he will yell at you when it's time to get off. Yongjusa is the name of the temple downstream from the bouldering. Once you are off of the bus look north. You will see an industrial looking place and the big highway will be on your right. Walk past this industrial building and there will be a little road that goes under the highway. Follow that road toward the end past the restaurants and it will turn into a trail. Keep following this trail past the workout area and the fenced off watershed. Boulders will be in the creek and on the hills. The best boulders are up the creek a while, or just off of the trail in the beginning. Have fun.
If all else fails just grab a cab and say 용주사 Yongjusa.
Nothing out of the ordinary.
The V0 - V10 is just a guess, who knows the hardest problems could be a lot easier or harder. Only time and a visit from some double digit pullers will tell.
Good restaurants are about 10ish min from the first boulders.
From what I can tell, there may be 3 bouldering areas of this quality in Yangsan. That's good news for any climbers in Busan too.
before you go... look for good rock, don't expect to see chalk on everything even if it get's climbed regularly. many of the easy to moderate problems have never any seen chalk, but this is changing slowly as more people go out.