user8488: Which opening traps do the Spanish Game (ruy lopez) offer - and are there experimental/alternate variations (apart from non 3. ...a6 variations) to the opening that could be forced on either side of the board?

user-1: I don't play the Lopez, so I can't answer the part relating to experimental variations, but I can list some of the common traps:
Tarrasch Trap in the Open Variation
After 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. 0-0 Nxe4 6. d4 b5 7. Bb3 d5 8. dxe5 Be6 9. c3 Be7 10. Re1 0-0 11. Nd4 Qd7?, White wins a piece:
[FEN "r4rk1/2pqbppp/p1n1b3/1p1pP3/3Nn3/1BP5/PP3PPP/RNBQR1K1 w - - 0 12"]


 12. Nxe6 Qxe6 (or fxe6) 13. Rxe4

Tarrasch Trap in the Steinitz Variation
After 1. e4 e5 2. Nf3 Nc6 3. Bb5 d6 4. d4 Bd7 5. Nc3 Nf6 6. 0-0 Be7 7. Re1 O-O, White wins a pawn:
[FEN "r2q1rk1/pppbbppp/2np1n2/1B2p3/3PP3/2N2N2/PPP2PPP/R1BQR1K1 w - - 0 8"]


 8. Bxc6 Bxc6 9. dxe5 dxe5 10. Qxd8 Raxd8 11. Nxe5

Mortimer trap
After 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. d3 Ne7 5. Nxe5?, Black wins a piece for 2 pawns:
[FEN "r1bqkb1r/ppppnppp/5n2/1B2N3/4P3/3P4/PPP2PPP/RNBQK2R b KQkq - 0 5"]


 5...c6 6. Nc4 d6 7. Ba4 b5 8. Bxb5 cxb5

Noah's Ark Trap
After 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 d6 5. d4 b5 6. Bb3 Nxd4 7. Nxd4 exd4 8. Qxd4?, Black wins a piece:
[FEN "r1bqkbnr/2p2ppp/p2p4/1p6/3QP3/1B6/PPP2PPP/RNB1K2R b KQkq - 0 8"]


 8... c5 9. Qd5 Be6 10. Qc6+ Bd7 11. Qd5 c4

Mate in the Exchange Variation
After 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Bxc6 dxc6 5. O-O Bg4 6. h3 h5 7. hxg4?, Black has good mating chances:
[FEN "r2qkbnr/1pp2pp1/p1p5/4p2p/4P1P1/5N2/PPPP1PP1/RNBQ1RK1 b kq - 0 7"]


 7... hxg4 8. Nxe5 Qh4 9. f3 g3 lead to mate

Mate in the mainline
After 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. Nc3 Bc5 6. Nxe5 Nxe5 7. d4 Bb4 8. dxe5 Nxe4 9. Qd4 Nxc3 10. bxc3 Ba5?, White has a mating attack:
[FEN "r1bqk2r/1ppp1ppp/p7/b3P3/B2Q4/2P5/P1P2PPP/R1B1K2R w KQkq - 0 11"]


 11. Ba3 b6 12. e6! Qf6 13. Bxd7+ Kd8 14. Bc6+! Qxd4 15. e7#

Suggestion for the community: should we turn this answer into a community wiki? I realise I've listed only a handful of traps.

8488: <p>Which opening traps do the Spanish Game (ruy lopez) offer - and are there experimental/alternate variations (apart from non 3. ...a6 variations) to the opening that could be forced on either side of the board?</p>
 -1: <p>I don't play the Lopez, so I can't answer the part relating to experimental variations, but I can list some of the common traps:</p>

<h2>Tarrasch Trap in the Open Variation</h2>

<p>After 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. 0-0 Nxe4 6. d4 b5 7. Bb3 d5 8. dxe5 Be6 9. c3 Be7 10. Re1 0-0 11. Nd4 Qd7?, White wins a piece:</p>

<pre><code>[FEN "r4rk1/2pqbppp/p1n1b3/1p1pP3/3Nn3/1BP5/PP3PPP/RNBQR1K1 w - - 0 12"]
</code></pre>

<blockquote class="spoiler">
  <p> 12. Nxe6 Qxe6 (or fxe6) 13. Rxe4</p>
</blockquote>

<h2>Tarrasch Trap in the Steinitz Variation</h2>

<p>After 1. e4 e5 2. Nf3 Nc6 3. Bb5 d6 4. d4 Bd7 5. Nc3 Nf6 6. 0-0 Be7 7. Re1 O-O, White wins a pawn:</p>

<pre><code>[FEN "r2q1rk1/pppbbppp/2np1n2/1B2p3/3PP3/2N2N2/PPP2PPP/R1BQR1K1 w - - 0 8"]
</code></pre>

<blockquote class="spoiler">
  <p> 8. Bxc6 Bxc6 9. dxe5 dxe5 10. Qxd8 Raxd8 11. Nxe5</p>
</blockquote>

<h2>Mortimer trap</h2>

<p>After 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. d3 Ne7 5. Nxe5?, Black wins a piece for 2 pawns:</p>

<pre><code>[FEN "r1bqkb1r/ppppnppp/5n2/1B2N3/4P3/3P4/PPP2PPP/RNBQK2R b KQkq - 0 5"]
</code></pre>

<blockquote class="spoiler">
  <p> 5...c6 6. Nc4 d6 7. Ba4 b5 8. Bxb5 cxb5</p>
</blockquote>

<h2>Noah's Ark Trap</h2>

<p>After 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 d6 5. d4 b5 6. Bb3 Nxd4 7. Nxd4 exd4 8. Qxd4?, Black wins a piece:</p>

<pre><code>[FEN "r1bqkbnr/2p2ppp/p2p4/1p6/3QP3/1B6/PPP2PPP/RNB1K2R b KQkq - 0 8"]
</code></pre>

<blockquote class="spoiler">
  <p> 8... c5 9. Qd5 Be6 10. Qc6+ Bd7 11. Qd5 c4</p>
</blockquote>

<h2>Mate in the Exchange Variation</h2>

<p>After 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Bxc6 dxc6 5. O-O Bg4 6. h3 h5 7. hxg4?, Black has good mating chances:</p>

<pre><code>[FEN "r2qkbnr/1pp2pp1/p1p5/4p2p/4P1P1/5N2/PPPP1PP1/RNBQ1RK1 b kq - 0 7"]
</code></pre>

<blockquote class="spoiler">
  <p> 7... hxg4 8. Nxe5 Qh4 9. f3 g3 lead to mate</p>
</blockquote>

<h2>Mate in the mainline</h2>

<p>After 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. Nc3 Bc5 6. Nxe5 Nxe5 7. d4 Bb4 8. dxe5 Nxe4 9. Qd4 Nxc3 10. bxc3 Ba5?, White has a mating attack:</p>

<pre><code>[FEN "r1bqk2r/1ppp1ppp/p7/b3P3/B2Q4/2P5/P1P2PPP/R1B1K2R w KQkq - 0 11"]
</code></pre>

<blockquote class="spoiler">
  <p> 11. Ba3 b6 12. e6! Qf6 13. Bxd7+ Kd8 14. Bc6+! Qxd4 15. e7#</p>
</blockquote>

<p>Suggestion for the community: should we turn this answer into a <strong>community wiki</strong>? I realise I've listed only a handful of traps.</p>
