diff --git a/docs/README.md b/docs/README.md
index 69c9242..4a03ca8 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -69,6 +69,7 @@
 | [**PGN**](#PGN) |  |
 | [PGN::__construct](#PGN__construct) |  |
 | [PGN::export](#PGNexport) |  |
+| [PGN::validate](#PGNvalidate) |  |
 | [PGN::set_tag](#PGNset_tag) |  |
 | [PGN::set_initial_fen](#PGNset_initial_fen) |  |
 | [PGN::unset_initial_fen](#PGNunset_initial_fen) |  |
@@ -1551,6 +1552,25 @@ PGN::export(  ): string
 
 
 
+---
+### PGN::validate
+
+
+
+```php
+PGN::validate(  ): void
+```
+
+
+
+
+
+**Return Value:**
+
+
+
+
+
 ---
 ### PGN::set_tag
 
diff --git a/src/PGN.php b/src/PGN.php
index a0bf1ed..18a1be0 100644
--- a/src/PGN.php
+++ b/src/PGN.php
@@ -40,6 +40,11 @@ public function export() : string
     return trim($pgn);
   }
 
+  public function validate() : void
+  {
+    $this->get_current_fen();
+  }
+
   public function set_tag(string $name, ?string $value) : void
   {
     if ($value !== null) {
@@ -111,6 +116,9 @@ public function get_current_fen(bool $as_object = false)
 
   public function get_fen_after_halfmove(int $halfmove_number, bool $as_object = false)
   {
+    if ($halfmove_number == 0) {
+      return $this->get_initial_fen($as_object);
+    }
     $halfmove_index = $this->get_halfmove_index($halfmove_number);
     $this->compute_fens($halfmove_number);
     if (!isset($this->fens[$halfmove_index])) {
@@ -154,7 +162,12 @@ private function compute_fens(int $max_halfmove_to_compute) : void
     }
     $fen = $this->get_last_computed_fen();
     for ($halfmove_number = sizeof($this->fens) + $this->get_initial_halfmove_number(); $halfmove_number <= $max_halfmove_to_compute; $halfmove_number ++) {
-      $fen->move($this->get_halfmove($halfmove_number));
+      $halfmove = $this->get_halfmove($halfmove_number);
+      try {
+        $fen->move($halfmove);
+      } catch (\Exception $e) {
+        throw new \Exception('Move ' . ceil($halfmove_number / 2) . ($halfmove_number % 2 ? '. ' : '... ') . $halfmove . ' is invalid. FEN ' . $this->get_fen_after_halfmove($halfmove_number - 1), 0, $e);
+      }
       $this->fens[] = $fen->copy();
     }
   }
diff --git a/tests/unit/PGNTest.php b/tests/unit/PGNTest.php
index 7c195e4..4902d63 100644
--- a/tests/unit/PGNTest.php
+++ b/tests/unit/PGNTest.php
@@ -8,6 +8,37 @@
 final class PGNTest extends TestCase
 {
 
+/*
+  public function testBugs() : void
+  {
+    $pgn = new PGN('[Event "Live Chess"]
+[Site "Chess.com"]
+[Date "2021.01.28"]
+[Round "?"]
+[White "djkvetak"]
+[Black "Nirrmall"]
+[Result "1-0"]
+[ECO "B01"]
+[WhiteElo "1126"]
+[BlackElo "1092"]
+[TimeControl "3600"]
+[EndTime "7:02:24 PST"]
+[Termination "djkvetak won by resignation"]
+
+1. e4 d5 2. exd5 Qxd5 3. c4 Qd8 4. d4 h6 5. Qh5 Nf6 6. Qf3 Qxd4 7. Nc3 Ng4 8.
+Be3 Nxe3 9. fxe3 Qd8 10. Qg3 e6 11. Nf3 g6 12. a3 Bd6 13. Ne5 Qe7 14. Nb5 Qf6
+15. O-O-O Bxe5 16. Nxc7+ Bxc7 17. Qxc7 O-O 18. Qd6 Rd8 19. Qxd8+ Qxd8 20. Rxd8+
+Kg7 21. Rxc8 Kf6 22. g3 Ke7 23. Bg2 a5 24. Bxb7 Ra7 25. Rxb8 Kd7 26. Bc8+ Kc7
+27. Rb7+ Rxb7 28. Bxb7 Kxb7 29. Rd1 Kb6 30. b4 a4 31. Kb1 f5 32. Rc1 Kc6 33. h3
+h5 34. Re1 g5 35. h4 g4 36. e4 f4 37. gxf4 Kd6 38. f5 exf5 39. exf5 g3 40. Rg1
+Ke5 41. Rxg3 Kxf5 42. b5 Kf4 43. Rg4+ Kxg4 44. b6 Kxh4 45. b7 Kg5 46. b8=Q h4
+47. c5 h3 48. Qb5 Kg4 49. Qc4+ Kg3 50. Qe4 h2 51. c6 Kf2 52. c7 Kg1 53. c8=Q
+h1=Q 54. Qc1+ Kh2 55. Qcxh1+ Kg3 1-0');
+    $pgn->validate();
+  }
+  */
+
+
   protected $samples = [
     '[Event "F/S Return Match"]
 [Site "Belgrade, Serbia JUG"]
@@ -125,5 +156,4 @@ public function testHalfmoveOutOfBoundsTooSmall2() : void
     $pgn->get_halfmove(1);
   }
 
-
 }