diff --git a/preface.asciidoc b/preface.asciidoc
index 6f6b578e..4fb82b1c 100644
--- a/preface.asciidoc
+++ b/preface.asciidoc
@@ -254,4 +254,5 @@ Following is a list of notable GitHub contributors, including their GitHub ID in
 * wjx
 * Wojciech Langiewicz (wlk)
 * Yancy Ribbens (yancyribbens)
+* Yoshimasa Tanabe (emag)
 * yurigeorgiev4((("", startref="acknowledge0")))