diff --git a/corne-cherry/doc/v2/buildguide_en.md b/corne-cherry/doc/v2/buildguide_en.md
index 1b91771..ef1584e 100644
--- a/corne-cherry/doc/v2/buildguide_en.md
+++ b/corne-cherry/doc/v2/buildguide_en.md
@@ -31,7 +31,7 @@ https://github.com/foostan/crkbd/blob/master/corne-cherry/doc/v3/buildguide_en.m
 | TRS (3-pole) cable | 1 | TRRS (4-pole) cable is also acceptable |
 | Micro USB cable | 1 | |
 
-### Options
+### Optional
 
 | Name | Count | Remarks |
 |:-|:-|:-|
@@ -53,7 +53,7 @@ left or right.
 
 ![02](https://user-images.githubusercontent.com/736191/54487432-789a6c00-48d9-11e9-87ea-3595b2f3ecc2.jpg)
 
-### Diode
+### Diodes
 
 Solder the diode of the chip part.
 You can attach it to either side, but in this build guide,
diff --git a/corne-cherry/doc/v3/buildguide_en.md b/corne-cherry/doc/v3/buildguide_en.md
index 008c8d8..204092f 100644
--- a/corne-cherry/doc/v3/buildguide_en.md
+++ b/corne-cherry/doc/v3/buildguide_en.md
@@ -28,7 +28,7 @@ https://github.com/foostan/crkbd/blob/master/corne-cherry/doc/v2/buildguide_en.m
 | TRRS (4 poles) cable | 1 | TRS (3 poles) cable is also acceptable |
 | Micro USB cable | 1 | |
 
-### Options
+### Optional
 
 | Name | Count | Remarks |
 |:-|:-|:-|
@@ -67,7 +67,7 @@ which are marked in red in the image below.*
 
 ## Assembly
 
-### Diode
+### Diodes
 
 Solder diodes for SMD components.
 Since SMD parts are very small,
diff --git a/corne-chocolate/doc/buildguide_en.md b/corne-chocolate/doc/buildguide_en.md
index f194227..3de0ff6 100644
--- a/corne-chocolate/doc/buildguide_en.md
+++ b/corne-chocolate/doc/buildguide_en.md
@@ -37,7 +37,7 @@ https://github.com/foostan/crkbd/blob/master/corne-cherry/doc/buildguide_en.md).
 |:-|:-|:-|
 | SK6812MINI | 54 | 42 for backlight, 12 for under-glow |
 
-## Preparation
+## Advance preparation
 
 If you build the firmware yourself,
 it will take some time to set up the environment,
diff --git a/corne-classic/doc/buildguide_en.md b/corne-classic/doc/buildguide_en.md
index 16a41ec..dfffef5 100644
--- a/corne-classic/doc/buildguide_en.md
+++ b/corne-classic/doc/buildguide_en.md
@@ -32,7 +32,7 @@
 
 ![image](https://user-images.githubusercontent.com/736191/40734610-e1ca0136-6473-11e8-8ac7-7bfa4b843f93.png)
 
-## Preparation
+## Advance preparation
 
 If you build the firmware yourself,
 it will take some time to set up the environment,
diff --git a/corne-light/doc/v1/buildguide_en.md b/corne-light/doc/v1/buildguide_en.md
index 3c0d7f8..1fd1250 100644
--- a/corne-light/doc/v1/buildguide_en.md
+++ b/corne-light/doc/v1/buildguide_en.md
@@ -131,7 +131,7 @@ Separate it if necessary.
 
 * Some versions do not have a jig.
 
-### diode
+### Diodes
 
 First, bend the legs of the reed type diode.
 
diff --git a/corne-light/doc/v2/buildguide_low_edition_en.md b/corne-light/doc/v2/buildguide_low_edition_en.md
index 1154501..1083583 100644
--- a/corne-light/doc/v2/buildguide_low_edition_en.md
+++ b/corne-light/doc/v2/buildguide_low_edition_en.md
@@ -27,7 +27,7 @@ This is the build guide for Corne Light v2 Low edition.
 | TRRS (4 poles) cable | 1 | TRS (3 poles) cable is also acceptable |
 | Micro USB cable | 1 | |
 
-### Options
+### Optional
 
 | Name | Count | Remarks |
 |:-|:-|:-|
@@ -65,7 +65,7 @@ which are marked in red in the image below.*
 
 ## Assembly
 
-### diode
+### Diodes
 
 Solder diodes for SMD components.
 Since SMD parts are very small,