Google N-gram Corpus Counts
╭─ーーー─┬───────┬───────╮
│ 蛟首　 │    54 │  3.0% │
│ チ首　 │    23 │  1.3% │
│ 螭首　 │     0 │  0.0% │
│ ちしゅ │ 1,731 │ 95.7% │
│ チしゅ │     0 │  0.0% │ - drop
╰─ーーー─┴───────┴───────╯

@@ -15,6 +14,0 @@
-<re_restr>蛟首</re_restr>
-<re_restr>螭首</re_restr>
-</r_ele>
-<r_ele>
-<reb>チしゅ</reb>
-<re_restr>チ首</re_restr>

蛟首	54
螭首	<20
チ首	23

@@ -5 +5 @@
-<keb>螭首</keb>
+<keb>蛟首</keb>
@@ -9,0 +10,3 @@
+<k_ele>
+<keb>螭首</keb>
+</k_ele>
@@ -11,0 +15,6 @@
+<re_restr>蛟首</re_restr>
+<re_restr>螭首</re_restr>
+</r_ele>
+<r_ele>
+<reb>チしゅ</reb>
+<re_restr>チ首</re_restr>
@@ -15 +24,3 @@
-<gloss g_type="expl">shape of a head of a mythical hornless dragon carved into stone</gloss>
+<xref type="see" seq="2817280">蛟・みずち</xref>
+<misc>&obsc;</misc>
+<gloss>carved head of a mizuchi</gloss>

daijiten, daijirin https://kotobank.jp/word/螭首-325246
https://ja.wikipedia.org/wiki/チ首
https://en.wikipedia.org/wiki/Chi_(mythology)

unwieldy gloss