On sa and za in Japanese

If it's the first word, pronounce the voiceless sawa.

If it follows another word, half its pronunciation is voiced zawa.

Just like Tan Tianhe and Tancheng, they are the first words at the beginning, so they are Qingyin Sawa.

Jitong, pronounced voiced zawa.

The law of writing is the same as that of reading, so you can write whatever you read.