I have found that the best method for me is...
...neither.
What I do is I go through each kanji in the book and on the koohii page, and get my favorite mnemonic into my head. Then I go to jisho.org and look up common words using that kanji and its onyomi, then add at least two of those words into my anki deck. I then do recognition reviews on those vocabulary words rather than reviews on RTK kanji to keyword or vice versa. This ensures that I am learning both useful vocabulary and the kanji's reading for when I encounter it in future words, rather than learning an abstract keyword that may or may not always correspond to the kanji's actual usage.
That isn't to say that RTK is not useful, quite the opposite, the only reason I am able to have decent retention is because I have the mnemonics to back me up if I forget what a kanji is supposed to imply. I just have the mnemonic lead me to a general concept rather than necessarily the specific RTK keyword.
Since it's my method, I'm biased, of course, but I feel this is the best way to gain and retain kanji information, at least for reading. The only exception IMO would be is if you want to do handwriting (as many do), in which case naturally keyword to kanji is necessary. Even then I feel there are various improvements that can be made upon the system. I think Japanese learning is going to look a lot different in five years.
...neither.
What I do is I go through each kanji in the book and on the koohii page, and get my favorite mnemonic into my head. Then I go to jisho.org and look up common words using that kanji and its onyomi, then add at least two of those words into my anki deck. I then do recognition reviews on those vocabulary words rather than reviews on RTK kanji to keyword or vice versa. This ensures that I am learning both useful vocabulary and the kanji's reading for when I encounter it in future words, rather than learning an abstract keyword that may or may not always correspond to the kanji's actual usage.
That isn't to say that RTK is not useful, quite the opposite, the only reason I am able to have decent retention is because I have the mnemonics to back me up if I forget what a kanji is supposed to imply. I just have the mnemonic lead me to a general concept rather than necessarily the specific RTK keyword.
Since it's my method, I'm biased, of course, but I feel this is the best way to gain and retain kanji information, at least for reading. The only exception IMO would be is if you want to do handwriting (as many do), in which case naturally keyword to kanji is necessary. Even then I feel there are various improvements that can be made upon the system. I think Japanese learning is going to look a lot different in five years.