08-13-2014, 12:31 PM
For your additional information, "first grade" means age 6 to 7 in Japan. These japanese children learn 80 kanjis for one year.
For the second grade (age 7 to 8), japanese children learn 160 kanjis. But as you see in the table, those 160 kanjis are much complicate compared to the first grade kanjis.
for the second grade kanjis, the "radical learning" seems to work well.