I would like have an section in wanikani about words categorized according to the subject. For example: sports section = 野球 (baseball), ボール (ball), etc…
I don’t know if have this kind of option but I think that would be fun create or categorize words by subject. The main subject would be thing like this: sports, food, health, family, house, tools, and infinite another things.
How do you think about it? Talk to me your opinion here. (Sorry for my english, I speak portuguese).
You mean in addition to the current “by level range” categorization?
I think it could be cool to have “tags” like “sports” for vocabulary and be able to look up vocab based on its “tag”.
Yes. I agree.
I passed on this request to the team, as it could be helpful, and you’re not the first to suggest something like this.
But I’d also like to share something I read recently in an ebook someone else on the forum (I don’t know remember who, sorry!) shared. The ebook is What do you need to know to learn a foreign language? by language teacher and research Paul Nation.
From page 32:
Although it seems like a good idea to learn related words at the same time, whether it
is helpful or not depends on the relationship between them. Words like near synonyms
(embarrass-humiliate, prevent-protect), opposites (hot-cold, long-short), and members
of a lexical set (days of the week, colours, the names of fruit, articles of clothing, parts
of the body) are best not learned together. The effect of learning them together is
so strong that it can make learning 50% to 100% more difficult. Being 100% more
difficult means that it would take twice as many repetitions to learn these words
compared to learning unrelated words. It has been suggested that where the related
words are nouns, objects which are nearer to each other in shape, apple-orange, are
more likely to interfere than objects which are different in shape, banana-orange.The relationship that helps learning is where the words are related as if in a story (frog,
pond, green, slimy, hop, croak). So, it is a good idea to note words from your reading
onto word cards as these words are unlikely to be members of the same lexical set.
I found this interesting because I learned a lot of vocabulary in sets like this, and whether it was harder for me or not, I can’t know unless I go back in time and try it the other way. But I believe what he said. I have experienced pairs of synonyms that gave me real trouble.
That said, I wonder if there could be a use for categorizing words like this on WaniKani. Maybe not drilling them all together, but… if they are grouped around an interest. Page 54, Paul Nation talks about keeping motivation by learning vocab and phrases around an interest. So something like sports, like you mentioned, might be helpful.
In any case, I’d like to see words grouped in some way, and then figure out a way to use them. And check out this ebook! I found it helpful and interesting.
What do you think about create a thematic months? For example: January - sports, February - house, etc. So January would have a option for learn sports thematic words… next month house, and so on…
Hmmm… maybe. I don’t know if this is something WaniKani would do, but centering your study around a certain theme during a month does sound like a good way to keep things fresh.
October… spooky vocab… 
I tried doing that on my own but it gets tricky figuring out how to group words. Some words could fit in multiple buckets. Like 球 could show up in sports or math. 
Instead of having a built in tagging system I think it’s better to take your own notes so you can group them how you like. I would rather have a filter option by verb, adjectives, and nouns.