What that block of text actually is, and how to read it yourself.
PGN stands for Portable Game Notation — it's the standard plain-text format almost every chess site and app uses to record a game. It's just text, which is why it can be copied, pasted, emailed, or stored in a plain file, and why See The Mate (and virtually every other chess tool) can read one directly.
A PGN file usually has two sections. First, a block of header tags in square brackets — things like <code>[Event "Rated Blitz game"]</code>, <code>[White "player1"]</code>, <code>[Black "player2"]</code>, <code>[Result "1-0"]</code>, and sometimes <code>[ECO "C50"]</code> for the opening code. These carry the metadata: who played, when, what the result was, and sometimes the opening name.
Second, the actual move list, written in standard algebraic notation: something like <code>1. e4 e5 2. Nf3 Nc6 3. Bb5 a6</code>. Each number marks a full move (one for White, one for Black), and each piece move uses standard shorthand — Nf3 means "knight to f3," O-O means castling kingside, and so on.
A few symbols show up often and are worth knowing: x means a capture (Nxe5 = knight captures on e5), + means check, # means checkmate, and =Q after a pawn move means promotion to a queen. Piece letters are K (king), Q (queen), R (rook), B (bishop), N (knight) — pawns have no letter, so "e4" alone means a pawn moved to e4.
Both chess.com and Lichess let you export any game as a PGN — on chess.com it's usually under Share → Copy PGN on the game page, and on Lichess it's available directly from the game's menu. Once you have that text, it can be pasted into any chess analysis tool, including See The Mate's Analyze page, and read back as a full move-by-move game.
Understanding PGN isn't just trivia — it's genuinely useful when a game won't load correctly, since being able to glance at the raw text and spot a missing result tag or a truncated move list is often enough to fix the problem yourself, without needing to re-export from scratch.
See the full range of import options in How to Load Your chess.com and Lichess Games, or paste a PGN directly on Analyze.