Side lines are not played as often as main lines, but it can be helpful to know how to play against (and punish) certain wanderings-away, as this can be a pleasant (and often quick) way to score points.
sainik - glaucokoltz
blitz, FICS, 2011
1.e4 e5 2.Nf3 Nc6 3.Bc4 h6 4.c3
This move is a decent alternative to the routine 4.0-0 in the Semi-Italian opening, one that shows up in 226 games in The Database and scores 69% for White.
4...Na5
I first covered this move when it appeared against 4.0-0 in "A Line of Play Everyone Should Know About"; and later in "Bully" and "A Hot Rocket to Oblivion". Currently The Database contains only 10 games with the 4.0-0 Na5 line, but 9 of them were won by White.
For the record, the fourth move alternative 4.Nc3 Na5 shows up in 49 games in The Database, with White scoring 86%; and 4.d3 Na5 shows up in 34 games, with White scoring 71%.
As for 4.c3 Na5, as in the current game, that shows up in The Database 88 times, with White scoring 88%.
5.Bxf7+ Kxf7 6.Nxe5+ Ke8
Black's best defense is 6...Ke6, but after 7.Qh5 his prospects are gloomy. Two possibilites: 7...Nf6 8.Qf5+ Ke7 9.Ng6+ Kf7 10.Nxh8 Kg8 11.Qxa5 Kxh8 and Black is down two pawns (although his King is safe); and 7...g5 8.d4 Nf6 (8...Qe7 9.Qg4+ Kd6 10.Ng6 followed by 11.Qf5) 9.Qf7+ Kd6 10.Ng6 Rh7 11.e5+ Kc6 12.Qxf6+, etc.
7.Qh5+ Ke7 8.Ng6+ Kf6 9.e5+
This wins, as does 9.Qf5#.
9...Ke6 Black resigned