"We thought this week's game was going to be William's 50th and then we went back through our records and realised it had been done against Rathkeale ... this week's is his 52nd," Lindisfarne College 1st XV coach Karl Jones explained.
"I only missed one game this season and one during the previous two seasons combined," Gunson said.
A 2014 Hawke's Bay under-16 rep who was invited to the Hawke's Bay under-18 camp this season, Gunson will head to Lincoln University in Canterbury next year to start a four-year land and property management course. He is keen to return to the Bay in future.
"I'll see how my rugby goes down in Canterbury. I may also travel overseas to play some rugby," Gunson said.
The 1st XI cricketer, who also plays basketball and volleyball for the school, Gunson ranks former Lindisfarne College head boy and new Magpie Hugh Renton as his hero. He is also grateful for the coaching he has received from Jones and former 1st XV coach Ben Spriggens.
"I regarded every game I played for the 1st XV as a highlight. The most memorable included last year's annual quadrangular tournament, which we won, and the 2014 one in Auckland when we finished third," Gunson recalled.
Another highlight this season was the team's competitive display against unbeaten Super 8 champions Hastings Boys' High School which was lost 32-14.
"We were pushing them close and they only got away on us when they brought a couple of their key players off the bench late in the second half," Gunson said.
A product of the Takapau junior rugby system, Gunson played for Hereworth School during years 7 and 8 and Lindisfarne College from year 9.
Former New Zealand Secondary Schools coach Jones believed Gunson, a quality lineout player, has the potential to follow a similar rugby path to former Magpies lock Tom Parsons, who is playing for the Turbos.
"As captain of our 1st XV, William hands out a pounamu taonga each week to our player of the day, who keeps it until the following week. While William would never give it to himself, he would have been our player of the day for three-quarters of our games," Jones said.
In addition to coaching Gunson in the 1st XV, Jones also coached him during his year 9 season. Jones said for any player to play 50 games for a school's 1st XV is considered a tremendous feat.
"The fact only eight players have done it in our school's history in an indication of its significance," he added.