Summer is not summer in Japan without two things: 1. Heat (OK, so maybe it’s not the heat, it’s the humidity); and 2 . . .

High school baseball.

Which means the national high school baseball tournament at Koshien Stadium in Nishinomiya, Hyogo Prefecture — due to start next week — with every single game broadcast nationally, courtesy of NHK.

Koshien is an event that is so established and so iconic that it is difficult to even imagine that Japan had summer prior to Meiji days and the introduction of baseball.

For what did people do back then? Just sweat and swat mosquitoes? No, old Japan must have skipped summer altogether and jumped straight from spring flowers to autumn leaves. But then baseball arrived to fill the gap, with the national tournament beginning in 1915. And thus Japanese summer was launched.

Sure, there is a spring high school baseball tournament as well, also held at Koshien. Yet, this spring fling is a weak sister when compared with the summer version.

For one thing, it’s an invitational. Teams do not battle their way up, win by win, in prefectural competitions as they do in the summer. For another, it lacks the seasonal impact. In the spring, Japanese focus on cherry blossoms, not baseball. Baseball and summer are like bacon and eggs, a natural fit. While baseball and spring are more like bacon and sherbet.

Spring and summer Koshien do share some traditions, but it’s in the summer that those traditions shine brightest, aided perhaps by a coat of perspiration. Leaving lasting images such as . . .

The frenetic, non-stop cheering of student bodies: Such groups are seated in what is known as the “Alps” section of the stadium. More than height, the reference is to distance. For to get from the student section to the playing field is like crossing the Alps. Suffice to say, the best seats they are not.

The singing of the school song by the victorious nine: This honor follows every game. And you would swear each song is the same. Lyrics of youth, guts and glory, all set to John Philip Sousa.

The gathering of dirt: Losing teams typically scoop infield soil into their bags as a memento of having played on Japan’s most hallowed field. For graduating players, to lose means their high school careers are over. Finished. Done. Caput. A career symbolized forever by that last handful of dirt.

Weeping: Is there any nation on earth that enjoys a good cry as much as Japan? Koshien, with its single-elimination dramatics, offers the perfect opportunity.

Student sections begin wailing with their final desperate out. Losing players sob as they collect their precious dirt. And television viewers across the land bite back tears in shared sympathy, an entire nation united as one in sniffles.

Summer swelter: Nothing says summer more than an NHK shot of a sun-broiled spectator fanning himself silly with a handheld fan, while trying to cool down with a cup of shaved ice.

My wife has about as much interest in baseball as she has in mud. Yet, she went to college in Nishinomiya and back then felt compelled to attend the games just for the sweaty romance of eating shaved ice at Koshien.

Youth itself: The do-or-die energy of the tournament enhances the fleeting nature of youth, which in all of us burns out in a roman candle of beauty, never to be recaptured. At Koshien, however, that beauty is yet remembered, as each tournament — or even each game — fires up anew the passion and hopes of younger days.

And the glory is as genuine as any glory anywhere. One day some young ballplayer from Countryville is a nobody and the next day he is a national hero. Television pumps his face into every home in the land. High school girls whom he will never ever meet swoon at his image.

And if the image is handsome and he can repeat his heroics in other games as well, he may lodge in Koshien history and remain forever young in the collective memory of the nation. Glorious? You bet.

So . . .

Who cares that endless sacrifice bunts, pick-off plays and other small-ball tactics rule high school baseball, making it as predictable as the turn of the seasons themselves. Even the primal screams of each new batter sound the same. Uniforms look alike as well. At Koshien, any team could be every team and no matter who wins, originality always loses.

And who cares that Koshien pitchers might hurl 150 pitches a game and then come back with little or no rest and do it all again in the next game. This from high school lads, when the World Baseball Classic limits its pitch count to “protect” the health of professionals. If you want a real reason to cry, here’s a good one.

But . . . it’s Koshien!

It’s traditional. It’s moving. And, yes without a doubt, it’s glorious.

And it wouldn’t be Japanese summer without it.