木村：今日のタイガースはなかなかよいですね。
鈴木：ピッチャーとキャッチャーの呼吸があっているし。
Kokyuu ga au
Kimura: Kyoo no taigaasu wa naka-naka yoi desu ne.
Suzuki: Picchaa to kyacchaa no kokyuu ga atte iru shi.
Kimura: The Tigers are in good form today, aren't they?
Suzuki: Yeah, the pitcher and catcher are really working in sync with each other.
Kokyuu ga au is a metaphorical expression used to describe two or more people who are working in such perfect harmony that you could almost say that (according to the literal meaning) even their breathing is in unison.
Lately it seems that soccer has overtaken baseball in popularity. Even so, Tokyo Dome is still packed out every night. Watching the pitcher and the catcher during a game, it's easy to see how/wton no kokyuu ga awanai to, umaku ikanai. (If they haven't got it together, things don't go well.)
In the world of music, shiki-sha to ensoo-ka no kokyuu ga au ka awanai ka ga mondai da. (The key is whether the conductor and the players are working in
sync.) I once went to see one of Seiji Ozawa's orchestra rehearsals. He responded instantaneously to each instrument, to each member of the orchestra, humming the melody as he explained. "Double bass, a little more gently; first violins, more like this..." I was so impressed; I thought you can see why he's such an internationally respected conductor. Moshi karera no kokyu ga awandkereba, kookyookyoku wa mecha-kucha na mono ni natte shimau. (If they weren't on the same wavelength, the whole symphony would be a mess.)
Playing doubles in tennis, playing soccer or basketball - anything which involves teamwork, kokyuu sae aeba, umaku iku koto ga ooi (Provided that you work in unison with the rest of your team, die chances are that things will go well.)
I've just started learning yoga, in which breathing is fundamental: Breathing in unison with the instructor, in and out. I think the expression kokyuu ga au is particularly appropriate in the context of yoga.