diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6fb2990..2612565 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## 2026-05-05 23:33 CEST — feat(go/M2.1): port czech.Normalize
+
+- First M2 pure-domain task: `internal/domain/czech.Normalize` (NFKD + Mn-strip + lowercase), byte-equivalent to Python `czech_utils.normalize`.
+- Adds `golang.org/x/text v0.36.0` as first external Go dependency.
+- 13-case table-driven test, all spot-checked against Python before locking.
+
 ## 2026-05-04 23:08 CEST — fix: payment inference exact-match short-circuit
 
 - `match_members()` now short-circuits on whole-word full-name hits; nickname/partial checks only run when no full name is present.
diff --git a/docs/plans/2026-05-03-2349-go-backend-rewrite-progress.md b/docs/plans/2026-05-03-2349-go-backend-rewrite-progress.md
index 54934e9..588424f 100644
--- a/docs/plans/2026-05-03-2349-go-backend-rewrite-progress.md
+++ b/docs/plans/2026-05-03-2349-go-backend-rewrite-progress.md
@@ -44,7 +44,7 @@ Goal: every pure function from the Python backend exists in Go with a parity tes
 
 Each task: port the function, write Go unit tests for fresh cases, hook into the Tier-1 parity runner.
 
-- [ ] **M2.1** `domain/czech.Normalize` — port [czech_utils.py](scripts/czech_utils.py) `normalize` (NFKD + combining-mark strip + lowercase)
+- [x] **M2.1** `domain/czech.Normalize` — port [czech_utils.py](scripts/czech_utils.py) `normalize` (NFKD + combining-mark strip + lowercase) — `20ade6d`
 - [ ] **M2.2** `domain/czech.ParseMonthReferences` — port `parse_month_references` (45 month declensions, range wrap, year inference)
 - [ ] **M2.3** `domain/fees.CalculateFee` — port [attendance.py](scripts/attendance.py) `calculate_fee` (constants table)
 - [ ] **M2.4** `domain/fees.CalculateJuniorFee` — port `calculate_junior_fee` with `Expected{Value int; Unknown bool}` for the `"?"` sentinel