I used this method last time and it "actually" works about 90% of the time. I failed once with this method and hence forth do not use it anymore. So surprised that someone is actually willing to share it with the english server side. Anyway here the translation goes:
All items including weapons, armor, shields etc...
+1->+3 Use normal upgrade scrolls 100%
+3->+4 One white and one red glow from anvil consecutively, use a NUS to +4 100%
+4->+5 One white 2 red glow from anvil consecutively, use a NUS 95%
+5->+6 2 ways:
First way: Wait for 3 red use BUS 80%, use NUS around 50%
Second way: Wair for 1 red 2 white use BUS 95%, use NUS around 60%
Explaination for 1 red 2 white:
Before red glow, anvil is shortly shut down for 10 seconds and above. During this time, when ppl upgrade, u wait for chance, consecutive 1 red glow and 2 white glow and u can upgrade. Note that using NUS to lure white glow is useless, ownself lure also useless, before upgrade, observe and see! If u r unsure of ya judgement, get a friend to help u lure these. Moreover, upgrading things is only a techinque, getting white glow needs more things. Getting white glow is effectively using a small stage of the success rate on the anvil
+6->+7 also 2 ways.
First way: 3 white glows. Ownself lure or friend lure also can. 4 sets of +2 items and use cursed to upgrade to +3. If continuous 3 sets goes to +3,then u can go ahead and upgrade to +7. Success rate is 50% plus. (Note: Have to be cursed scrolls) +4, +5, +6 also can use this method but its hard to lure and its costly and price of cursed scrolls are now high, so below +7 its not recommended.
Second way: 5 red and upgrade to +7. All methods of luring 5 red I had also tried but this method works the best. 4 sets of +4 items and use cursed to +5. Lure 3 red glows yourself using this. Then, prepare 5 sets of +5 items, use a NUS to +6 (success to +6 quite high), if burned, OK! Use a +5 item and a normal elemental scroll to add elemental to that item, if success, cost of burning can be recovered back. 90% it will fail. If fail, then its very good. Use your desired item to +7 success rate is about 50%. The cost of upgrading using this method is rather high. Unqiue weapons and shields to +6 can use this method, success rate 70%. Personally i feel that unqiue weapons are easier to upgrade... Its the best and most practical way now. Another important note: before u upgrade, u need to oveserve the anvil carefully. Observe for a period of time and u can roughly judge whether the red glows are lured by cursed scrolls or izzit someone who broke a chitin or other good stuffs. When the anvil glows red not by the lure of cursed scrolls, it may not be such a good thing. During this time, its not wise to rush for upgrades, need to wait until the anvil is stable then u upgrade. Whether the anvil is stabel or not, u can use these methods to judge it out:
Using cursed scrolls to upgrade 4 sets of +3 if success rate is 50% and above, or anvil white red ??? (dont understand wat author trying to say) anvil during this time is stable, and upgrading success rate is very high. Using method above will lead to very high success rate.