Some studying tips. Most of these are common sense but it's worth repeating.
>A healthy body leads to a healthy mind
If you're struggling, exercise. Fat leads to excess estrogen production and lower T-levels making you act like an emotional brat, so exercise. If you're struggling, go for a mile walk or a short swim then come back to it. Do leg day. Your thighs are the second largest testosterone power house in the body, and strain on the glutes has been directly linked to bodily signals to produce more. Naturally produced testosterone has been directly shown to help with focus.
Carbs might make some anons sleepy, but a small bit of sugar (like a mini candy bar's worth or a glass of milk) while studying has been shown to significantly increase retention by activating these reward pathways. The best time to ingest is mid-completion, since your body will naturally produce reward hormones post-completion. This is also why alcohol works since it effects similar pathways and why wine (higher in sugar content) is one of the best alcoholic study drinks followed by malt-heavy beers.
*Avoid chewing gum while studying because your brain will associate the correct answer with the smell/texture of gum which can screw you over when you don't have gum.
This can't be stressed enough, but don't cram. The only proper way to learn Japanese or learn a specific kanji is to use it daily. Anon might learn everything in a day and move on, he might even actually memorize them doing this method, but he's going to hit a roadblock down the line while the anon who struggles but practices old words daily is going to retain them in his long-term memory.