In a key moment late in last year's Interscholastic League of Honolulu first-round showdown between Kamehameha and Punahou, a Kamehameha touchdown closed the score to 14-13 and the Warriors elected to go for the two-point conversion after an encroachment penalty moved the ball to just outside the 1-yard line.

The attempt failed, as the Kamehameha tailback was tackled at the line of scrimmage and the Buffanblu hung on for the crucial victory.

If a similar scenario develops in tonight's Kamehameha-Punahou ILH Division I opener, a different decision might be made. That is because for the first time, the league has adopted overtime play in the event of a tie at the end of regulation.

"It's a one-year experiment," ILH executive director Don Botelho said.

The overtime rules are the same as college (each team gets a first-and-10), except the ball is placed at the 20-yard line instead of the 25 and there is no requirement to go for a two-point conversion after the third touchdown.

The O'ahu Interscholastic Association voted down a proposal to invoke an overtime rule.

Here is a closer look at tonight's key games:

NO. 2 PUNAHOU VS. NO. 6 KAMEHAMEHA

WHEN: Tonight, 7:30

WHERE: Aloha Stadium

Records: Kamehameha 1-0-1 overall; Punahou 2-0

Last week: Both were idle

Notable: Two of the Buffanblu's most explosive players, running back Dalton Hilliard and linebacker/fullback Manti Te'o, sat out the Buffanblu's 28-19 victory over Leilehua two weeks ago while nursing injuries, but both are expected to play tonight. ... Kamehameha is coming off a 21-21 tie with Campbell in which it took a 21-0 halftime lead, only to see the Sabers rally in the second half. Warriors quarterback Michael Hoke completed 14 of 21 passes for 244 yards, with one interception, and added 56 yards rushing on nine carries. ... Punahou alternated two quarterbacks against Leilehua, with Kimo Makaula completing 12 of 16 passes for 157 yards and one touchdown and Cayman Shutter adding 8 completions in 14 attempts for 96 yards and three more touchdowns. ... Kamehameha wide receiver Kupono Haitsuka's father, Jeff Cabral, is a Punahou assistant coach.

NO. 4 WAI'ANAE VS. NO. 9 LEILEHUA

WHEN: Tonight, 7:30

WHERE: Raymond Torii Stadium, Wai'anae

Records: Leilehua 2-2 overall, 1-1 OIA West; Wai'anae 4-0, 2-0

Last week: Leilehua lost to Mililani, 16-14; Wai'anae defeated Campbell by forfeit

Notable: Leilehua lost last week only after Mililani kicked a field goal with 43 seconds remaining. Leilehua's Allan Macam caught eight passes for 114 yards, but the Mules also were intercepted three times. ... Wai'anae has been winning with defense, allowing only 13 second-half points total in the three games won on the field. The Seariders have mostly stuck to the ground on offense, with quarterback Ben McQuown attempting only eight passes in each of the three games.

NO. 10 CASTLE VS. KALAHEO

WHEN: Tonight, 7:30

WHERE: Kailua Stadium

Records: Castle 2-2 overall, 2-0 OIA East; Kalaheo 3-1, 1-1

Last week: Castle defeated Moanalua, 27-13; Kalaheo lost to Kahuku, 33-26

Notable: Castle quarterback Blake Rapozo completed 23 of 29 passes for 218 yards and two touchdowns against Moanalua. ... Kalaheo quarterback Cody vonAppen also is coming off a productive game, with 213 yards passing and 40 yards rushing. ... Kalaheo has not beaten Castle since a 53-21 victory in 1997.

Read Wes Nakama's blog on prep sports at http://blogs.honoluluadvertiser.com

Reach Wes Nakama at wnakama@honoluluadvertiser.com.