@hakui @hfaust It is nonfree.

It is advertised as being gratis, but that only applies for trivial usages;
For commercial use, up to 20 items per creation may be used free of charge. If the number of items exceeds this limit, a fee of approximately ¥1,000 (excluding tax) per item will be charged for each item (including the first 20). There is no limit on the number of items used for personal or non-commercial use, as well as use by businesses small enough to not require tax returns.