Not quite like Paul Charles Morphy
When I play some unrated blitz games on the Internets, I am often paired with random p1300s who always insist on playing the Philidor opening like Count Isouard and the Duke of Brunswick did vs. P.C. Morphy..
I don't know if you know this game: Morphy was white and went all-in on black's weakling play starting immediately on the flop. Those counts couldn't play proper chess while Morphy on the other hand was fairly proficient in ripping apart people who had more important things to do than playing children's board games. Replay the game on the website http://www.chessgames.com/perl/chessgame?gid=1233404.
If you are rated around 1300 and you are overly excited to "play like Morphy", DO NOT play this thing as black and especially not on the Internet. It's a complete giveaway you are a chess dummy wanting to be slaughtered.
And they don't seem to understand - I have played against this crappy opening literally dozens and dozens of times and always against different p1300 players. I'll repeat: Morphy did NOT play this. MORPHY was NOT black. I can't start imagining the amount of 1300s playing chess on the web on this very moment who have memorized the Morphy game and are playing 1. ... e5 2. ... d6 3. ... Bg4 AS BLACK - like the newbie Count & Duke. Silly chess-playing Americans. They are playing chess like a couple of chess-nitwits over one hundred and fifty years ago; most certainly NOT emulating the play of one of the first chess geniuses.
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Don't get me wrong, the Philidor is very playable if you're somewhat stronger and have a couple of justifying ideas under your belt like gambiting a pawn somewhere. But 3. ... Bg4 is a big no-no in my unrated-p1300 experience.
You can say "but hey they would lose whatever they play, it is INEVITABLE in any case", but my advice still stands: you 1300s should play more poker-like opening moves instead, not giving away anything of your feeble intentions; it is much more promising than immediately showing one of your low cards. I'll go all-in.