diff --git a/ngochess/gtp/util.go b/ngochess/gtp/util.go
new file mode 100644
index 0000000..b9e774c
--- /dev/null
+++ b/ngochess/gtp/util.go
@@ -0,0 +1,31 @@
+package gtp
+
+import (
+	"fmt"
+	"git.noahlan.cn/noahlan/ntool/nmath"
+	"strings"
+)
+
+const alpha = "abcdefghjklmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ" // 无 'I' 的alpha
+
+func Point(x, y int) string {
+	if x < 0 || x >= 50 || y < 0 || y >= 50 {
+		return ""
+	}
+	return fmt.Sprintf("%s%d", byteToString(alpha[x]), y+1)
+}
+
+func byteToString(b byte) string {
+	return string([]byte{b})
+}
+
+func ParsePoint(pos string) (x, y int) {
+	x = byteToIndex(pos[0])
+	y, _ = nmath.Int(pos[1:])
+	y = y - 1
+	return
+}
+
+func byteToIndex(b byte) int {
+	return strings.Index(alpha, string([]byte{b}))
+}