The shrinkage of teams participating in the state football tournament’s three tiers this season — a reduction from 20 entries to just 12 — changed the flow.

That’s why each weekend of the First Hawaiian Bank/HHSAA Football State Championships has taken on a different flavor. For the viewing public, the results have been more than palatable. Last week’s matchups wound up with five thrillers out of the six contests.

This weekend, the Division I and II brackets are on hold. The Open Division semifinals kick off at 4:30 p.m. today at Aloha Stadium when Kahuku meets Waianae in a matchup of the Oahu Interscholastic Association’s champion and third-place team.

In the nightcap, defending state champion and No. 1-ranked Saint Louis takes the field against OIA runner-up and third-ranked Mililani. It’s a pairing of teams with similar offensive features and coaches who love hard-nosed football in the trenches.

After all, Saint Louis coach Cal Lee played linebacker in high school and college, and has taught the nuances of linebacker and defense for decades.

Mililani coach Rod York played defensive tackle at ‘Iolani and Hawaii, and the Trojans are at their best when their sledgehammer linebackers are focused on the defensive side of the ball. Jalen Olomua and Darius Muasau are talented enough that they are still in the offensive rotation at running back.

It’s almost two peas in a pod, Lee and York.

“We have a good rapport. I don’t talk to him before I play him the next day, but in the offseason, we always chat,” Lee said. “We’ve gone to clinics. I took him to a couple, and we got to know each other.

“He always asks questions, and that’s how you get better. That’s what I did before, asked questions. I remember watching him when he was playing at UH. We’d sit underneath the tree. The dad (Rod Tanu) was there, and we’d watch him play. A few years later, he’s coaching and doing a good job, too.”

York has enjoyed spending time with Lee brothers Cal and Ron.

“It’s an eerie matchup for us. Me, personally, I owe a lot to Coach Cal and Coach Ron. I’m invited by him to go to these clinics,” York said. “I’m exposed to great coaching, to see how he thinks and how he handles things, and we have a fun time.

“There’s also some Kahuku coaches. We’re all friends off the field. He’s the most productive coach in the history of Hawaii high school football, and a lot of the good coaching that’s come out of Hawaii has gone through Saint Louis.”

Mililani was 10-0 before last week’s 35-31 loss to Kahuku in the OIA final.

ILH champion Saint Louis (8-0) has been idle for two weekends. Everyone — from quarterback Chevan Cordeiro (2,162 passing yards, 325 rushing yards, 30 combined TDs) to junior defensive tackle Faatui Tuitele (18 scholarship offers) to All-State linebacker Noa Purcell — got time to rest and heal. The break has also given Lee and his staff more time to prepare. His mind is always coming from a defensive perspective.

“He’s a good quarterback,” Lee said of Mililani junior Dillon Gabriel, who has passed for 2,719 yards and 29 TDs with seven picks. “He can throw it and run a lot, make you miss tackles. We practice for that. We have to go after him. We’ve got to make sure we have great coverage on him.”

Saint Louis’ front seven has been superb, but Lee’s stress level has been a bit higher of late.

“There’s a lot of sleepless nights. You ever try to go to sleep thinking about the game? It’s not easy,” he said. “You start going to Longs (Drugs) and getting sleeping pills.”

The same might be said of his counterparts at Mililani. The Trojans were stellar in the early going, had a 21-7 lead, and Kahuku’s offense struggled with turnovers. For a long moment, it felt like Mililani was a team destined to knock Kahuku off the OIA throne.

Now, the Trojans will face perhaps the most potent offense in the state, though some spectators might point to the lack of a smash-mouth ground game as a weak spot for Saint Louis. Does it matter? The Crusaders scored 45 points per game against a menu of foes who were almost entirely in the Top 10. Defensively, they allowed just 13 points per game.

“Saint Louis is the type of program, they’re going to do what they did to get us here,” York said. “That defense that they’ve been showing, they’re going to show it against us. Why not? They’ve been dominating teams, so why would you change it? I expect two or three looks.

“The rest is a chess match. We try to find a weak spot, the matchups and openings, and when we have them, we try to exploit them.”

One thing York and Lee agree fully on is the botched call during the OIA final that cost Mililani a touchdown. Gabriel’s quick-kick punt caromed off one of his blockers. He caught the ball and threw an apparent touchdown pass that was negated by officials, who conferred for several minutes and called illegal man downfield. The head of OIA officials later acknowledged that the call was wrong and a touchdown should have been counted.

Lee watched the footage and was stunned.

“That was the wrong call,” he said. “Nobody was downfield. It’s too bad they couldn’t review. You put in a lot of time and effort, and find out later it’s a legal play.

“It’s too late. If they had instant replay, they would’ve fixed it. They have the facilities at Aloha Stadium. It’s unfortunate that it could happen.”

York is over it, mostly.

“For me, the game is over. We didn’t lose the game because of that,” he said. “The only thing I didn’t like is they straight lied and said ‘illegal man downfield.’

“That did not happen. The player they called it on was 4 yards behind the line of scrimmage. That was not human error. But credit to Kahuku, their players and coaches because they came back. They fought hard and earned the win.”

The deeper in the season they go, the Kahuku Red Raiders are stretching, growing, expanding into a new creation. The OIA championship win over Mililani was an instant classic, an epic night that forced Big Red to dig deep. A resilient front seven of Mililani challenged Sol-Jay Maiava and his offensive unit to come up with big plays in new ways. One key result: Two-way skills player Kaonohi Kaniho hauled in the go-ahead touchdown in the final minutes.

There’s no time to rest. Kahuku is now in a state semifinal against ancient nemesis Waianae. When the teams met in the league opener three months ago, Kahuku won 37-0, one of three losses for Waianae to start the year. Couple that fact with the emotion of the OIA title win, and the Red Raiders are aware of any potential slippage.

“Coming off a big game, we want to avoid a mental letdown,” Red Raiders coach Makoa Freitas said. “Waianae, when they run the ball, it’s kind of an option, so you have to know your assignments, stay in your lanes and be sharp mentally.”

The Seariders eked out a 29-21 overtime win over Campbell to claim third place in the OIA plus a state berth. Rico Rosario, playing on a sore ankle, entered the game in the second half and ran for 66 yards and two TDs. Whatever confidence Waianae gained from a clutch victory, Kahuku can probably match after outlasting Mililani.

“I think it showed other people that our team is mentally tough, and we have players who persevere through adversity,” Freitas said. “I’m glad everyone got to see it.”

Maiava was on crutches after the game, but Freitas expects him to be healthy enough to suit up for Waianae.

“We have some dings, but everybody will be fine,” he said.

Maiava’s post-touchdown celebration in the first half, a dance routine that is now fodder on Twitter with its mirror-image effects and funky techno music, wasn’t exactly what Freitas and his staff had drawn up.

“He plays with a lot of passion and a lot of intensity. He was excited and, you know, we got the penalty,” Freitas said. “He’s a young man and made a big play. I talked to him. It’s unsportsmanlike, so one more and you get disqualified.”

Waianae’s sturdy defense is led by hybrid linebacker/playmaker Kana‘i Mauga, a commit to USC. A huge performance by junior defensive tackle Zefften Avilla-Thompson — three sacks — was a key factor last week. The front seven has to face a Kahuku offensive line led by Enokk Vimahi (12 scholarship offers) and a backfield that includes big bruiser Sione Mahe, shifty Enoch Nawahine and a posse of hungry ballcarriers that includes J.L. Lavea and Toalei Lefau.

Maiava had problems hanging on to the ball in the first half against Mililani, but settled in and finished with a career-high 248 passing yards, including the clutch TD toss to Kaniho. The sophomore now has 1,123 passing yards and 10 TD strikes with just three picks in eight games.

The Seariders, who didn’t complete a pass in the win over Campbell, will be tested. Kahuku’s defense, which has permitted just 81 points in 10 games, is led by DE Samson Reed (Virginia commit), DT Sedric Iafeta (offers from Hawaii, Navy) and DL/LB Sekope Latu (offer from BYU). LB Miki Ah You (four offers), LB/S Nalu Emerson (Hawaii offer), LB/RB Lavea and DB/WR Kaniho.