ok oh ama . ▁The ▁official ▁name ▁of ▁the ▁Blue ▁Line ▁is ▁" Y ok oh ama ▁Municipal ▁Sub way ▁Line ▁ 1 " ▁and ▁" Y ok oh ama ▁Municipal ▁Sub way ▁Line ▁ 3 "; ▁Line ▁ 1 ▁runs ▁from ▁K ann ai ▁to ▁Sh on and ai ▁while ▁Line ▁ 3 ▁runs ▁from ▁K ann ai ▁to ▁Az am ino . ▁However , ▁all ▁trains ▁passing ▁through ▁K ann ai ▁directly ▁operate ▁between ▁Line ▁ 1 ▁and ▁Line ▁ 3 . ▁ ▁Due ▁to ▁the ▁opening ▁of ▁Line ▁ 4 ▁( known ▁as ▁the ▁Green ▁Line ), ▁the ▁line ▁has ▁been ▁market ed ▁as ▁the ▁" Blue ▁Line " ▁since ▁ 3 0 ▁March ▁ 2 0 0 8 ; ▁its ▁origin ▁came ▁from ▁" Blue " ▁being ▁a ▁symbol ▁of ▁Y ok oh ama ▁due ▁to ▁its ▁color ▁( it ▁has ▁been ▁used ▁in ▁vehicles ▁and ▁signs ▁from ▁the ▁time ▁of ▁opening , ▁since ▁it ▁is ▁recognized ▁as ▁the ▁image ▁color ▁of ▁the ▁route ). ▁The ▁line ▁color ▁is ▁blue ▁and ▁the ▁line ▁symbol ▁used ▁in ▁the ▁station ▁number ing ▁is ▁B . ▁ ▁Over view ▁ ▁The ▁Blue ▁Line ▁consists ▁of ▁two ▁routes ▁( known ▁as ▁Line ▁ 1 ▁and ▁Line ▁ 3 ). ▁Line ▁ 1 ▁starts ▁from ▁Sh on and ai ▁in ▁F uj is awa , ▁runs ▁through ▁T ots uka , ▁Kam io oka , ▁and ▁I se zak ich ō j am achi , ▁and ▁termin ates ▁at ▁K ann ai ▁in ▁central