is to import japanize_matplotlib. When you import japanize_matplotlib, the font used by matplotlib becomes one that supports Japanese. If you check with plt.rcParams['font.family'], you can confirm ...

<p>If you are working with any kind of NLP in Python that involves Japanese, it is paramount to be able to view summary statics in the form of graphs that in one way or another includes Japanese ...

The Kaggle environment (Linux) does not have Japanese fonts installed by default. Therefore, when you try to display Japanese, the system cannot find the corresponding font and displays it as " ".