Both scripts come from Chinese characters, but from different sources:

• Hiragana: Developed from cursive forms of whole Chinese characters (草書体). Monks and women used these flowing shapes for poetry and personal writing.
• Katakana: Created from fragments of Chinese characters. Buddhist monks used these angular shapes to annotate Chinese texts with Japanese pronunciation.

The visual distinction helps your brain instantly recognize "this is foreign" (katakana) vs "this is native Japanese" (hiragana) when reading.

The 長音符 (chōonpu) or "ー" mark extends the previous vowel sound:

• コーヒー (kōhī) - coffee
• ケーキ (kēki) - cake
• メール (mēru) - email

It's almost exclusively used in katakana for foreign words. In hiragana, you'd write out the full vowel (おかあさん not おかーさん).

This mark helps preserve the original pronunciation of foreign words, since Japanese doesn't naturally have long vowels in the same positions as other languages.

Katakana has special combinations to represent foreign sounds that don't exist in Japanese:

These didn't exist in traditional Japanese, so they were created specifically to better approximate foreign pronunciations.

These are the most confusing katakana pairs. The difference is in stroke direction:

Memory trick: In "tsu" the dots go "two" (vertical, like || ), in "shi" they "sheet" across (horizontal, like =).