[z2]

For pinyin representation of Mandarin, these are very different sounds, while the equivalent (identical) Mandarin pinyin representation of し, じ, つ would be xi, ji, cu. I'm not as familiar with romanization systems closer to Latin pronunciations, but for Wade Giles it would probably be written like shi, chi, tsu.

[nth233]

Not exactly. In the Wade–Giles system:

xi → hsi ji → chi ci → tz'u