hieroglyphics
Japan has hundreds themselves
Korean has fewer “letters” than English
The Japanese have 3 sets of “characters”
The Kanji are borrowed from the Chinese and depending on how they are used either have an Un pronunciation or a Kun pronunciation. They express ideas similar to the Chinese with each character, but sometimes use them specifically for their phoenetic value to pronounce a Japanese word.
The Hirigana consists of about 46 kana (+2 not used anymore) indicate the 46 sounds in the language. There are only 46 phoenetic sounds nothing more nothing less. It was created for words that didn’t have a corresponding chinese character. Some are the same base kana with just an extra tick or circle to indicate a minor modification. So fu, bu, and pu are the same base with mods and have similar mouth shapes that progress. Or da vs ta as well. Often a combination of Kanji and Hirigana is used to create the japanese word as the kanji by itself won’t give the correct pronunciation.
The Katakana is similar to Hirigana but slightly modified and only used for foreign words - such as terebi which is japanese for television or a-to-mo-bi-ru. It isn’t combined with Kanji in usage.
Romaji is the last and is basically the alpahbet as we know it. Typically like with Katakana used for foreign words, teaching japanese to foreigners, advertising.
However - All you need to really be able to communicate in writing is one of the last three if you know the spoken vocabulary. It’ll come across crass or stilted, but if all you can do is write hirigana you can still write back and forth with someone. Katakana doesn’t work as well as Romanji in my view for doing the same, but it is possible.
Chinese on the other hand is a tonal language so on top of their hanzi character issue requiring thousands for true litracy you also have to be able to detect changes in pitch or tone that reflect a change in meaning for the words. So ma with a flat tone means mother (early mouth form for kids so common across languages), but ma with a down up tone means horse - not sure about you, but I never found it good to call my mom a horse’s ass. ;)
Mandarin has 4 tones, Cantonese has 5 and they can’t communicate between the two unless one either knows both or they know the hanzi to write with - because the characters retain their meaning independent of how they are pronounced.