Vacuum master for XH201

Used automobile parts arrived from Chiba Pref. this morning, replacement parts brake master back & master cylinder assembly for B-Vectra, though I imagined that the 1 way valve should be equipped in vacuum connecting nipple, it was in vain, XH201 parts was the same as for that for XH200. Judging from the tendency seen in domestic produced models, independent 1 way valve in the vacuum line is the most unlikely, I feel some lack of sophistication in automobile parts productive designing.