diff --git a/progress.md b/progress.md
index 58e21f4..b9c828a 100644
--- a/progress.md
+++ b/progress.md
@@ -110,7 +110,7 @@
  - [ ] 12.6 Example: Decoding S-Expressions
  - [ ] 12.7 Accessing Struct Field Tags
  - [x] 12.8 Displaying the Methods of a Type
- - [ ] 12.9 A Word of Caution
+ - [x] 12.9 A Word of Caution
 - [x] Chapter 13: Low-Level Programming
  - [x] 13.1 unsafe.Sizeof, Alignof, and Offsetof
  - [x] 13.2 unsafe.Pointer