question regarding coaching

i'm thinking that in the future i will want to become a chess coach or teacher, but i only ever play 1. d4, and i never play 1. e4, which is what most people play, so if i were to look over students games, i wouldnt be so good at analysing games arising from 1.e4 for white. when i tried playing 1.e4, i did quite badly. is it necessary to learn this?

Presumably you have to play against it. What lines do you play?

Yes, if you want to coach chess, you absolutely must have working knowledge and experience of the world's (and history's) most popular first move in chess, 1.e4!  In fact, most chess instructors say that, when teaching openings, you should start with the double king pawn opening because it most efficiently and quickly demonstrates the main opening principles (control the center, develop minor pieces quickly, castle quickly).

I mainly play 1.Nf3 and 1.d4 now because I like to delay confrontation (knowing from experience that most players are impatient and will be tempted to attack prematurely).  But I spent most of my career playing 1.e4, and I'm glad I did.  When teaching chess to novices, I first spend lots of time on 1.e4 e5 and the resulting tactical fireworks.  Next I look at the Sicilian, French, and Caro Kann. Then finally 1.d4 (Queen's Gambit, KID, Dutch), 1.Nf3 (KIA), and some hypermodern weirdness.

thanks leo! guess i need to learn e4 e5. when i play vs e4, i play the caro kann and the sicilian. i used to play the french but that was when i was less than 1700 rated so i still dont know as much as i should. i used to play 1.e4 and i did the ponziani but stopped when i was like 1600 rated. do you think i should learn all the variations in 1.e4? (pirc, ruy lopez, italian game, russian defence, phillidor) 

1.e4 is a very good opening move (like 1.d4), but yes, as a chess intructor/tutor you need to know about white's main plans in the Ruy Lopez, Italian, Open Sicilian, Caro Kann, French, and Scandanavian.  You will be asked about these!  That should be enough for starters.  That is quite a bit to learn, so I would delay studying white's lines in the Pirc/Modern, Philidor, Alekhine, and Petroff defenses until later (these are much less commonly encountered anyway).  The off-beat defenses like the Nimzowitch and flank defenses could be explored on a need-to-know basis since these are the least common of all, and can be adequately handled using general principles, without any memorization.

Even though as an instructor you need to know more about openings than your typical students, please don't let your students make the mistake of becomming obsessed with openings.  Many students stress about (or fall in love with) memorizing opening sequences.  But it is much more productive to emphasize general opening principles (control/occupy center with 1 or 2 pawns, develop knights and bishops quickly, don't move the same piece twice, castle early, centralize rooks, lastly develop the queen).

Also, most instructors would agree that you should give the most importance to endgames and tactics.  And the idea of always examining all forcing moves (checks and captures) on each turn.

I wish you success.  I've been where you are now.  Feel free to ask more questions as they come up.  I'll be glad to offer suggestions.

I think it will depend on the level of players you're going to teach.

For intermediate students below, I doubt it'll be necessary, but you do need to know general principles, theory, and plans. Like the different kinds of centers and how to play them or against them - open, closed, fixed, and mobile centers. Those will never change regardless of the opening. Actually, they're even applicable in Chess960.

If you can only coach someone in a particular type of opening, then your knowledge might be specific to certain structures. You can always coach on those too, if that's what a student wants to learn.