On Kensington Park Number 1, City batted the large part of the day to post 253 for 9 declared.
In early trouble at 2 for 6, City had captain Rory Darkins and Northern District representative Joey Yovich to thank for their recovery as they shared in a 146 run, 3rd wicket stand.
Darkins scored 72, while Yovich, enjoying a long stint at the wicket before the first class season resumes, scored 83.
Chris Page chimed in with 43.
Tom Herman, recently returning to Onerahi from Whangarei Boys' High School, bowled particularly well, sending down 23 and taking 5 for 43.
Onerahi were 23 for no loss at the close of play.
Meanwhile, on the number 2 ground, another Child was causing havoc for opposing batsmen. WBHS senior pro John Child took 7 for 49 in aiding the students to dismiss Kamo for 137.
Showing great stamina, Child bowled an 11-over first spell then returned for a 17-over second spell.
While his knees and ankles won't thank him for it, it was the standout performance of the day and he was justly rewarded for a fine display of swing and seam bowling.
In reply, WBHS are 71 for 4 in reply with Ben Smith and Max Hamilton left not out at the close.