Image source, Getty Images
Ireland scored six tries as they opened their World Cup in style in Northampton
Orla Bannon
BBC Sport NI Journalist at Franklin's Gardens
Women's World Cup - Pool C
Ireland (28) 42
Tries: Costigan, Jones, Parsons, Tuite, Higgins, Breen Cons: O'Brien 6
Japan (7) 14
Tries: Hirotsu, Kawamura Cons: Otsuka 2
Ireland opened their World Cup campaign with a six-try victory over Japan in an impressive display at Franklin's Gardens.
Eight years on from their last appearance at a World Cup finals, this was an early statement of intent from Ireland with six different try scorers in Northampton.
Amee-Leigh Costigan, Neve Jones, Beibhinn Parsons and Fiona Tuite had the bonus point wrapped up before half-time with further second-half tries from Eve Higgins and Enya Breen.
All six were converted by Dannah O'Brien.
Japan scored a try in each half from Haruka Hirotsu and Masami Kawamura before Ireland lost prop Linda Djougang to the sin-bin late on.
Ireland play Spain in a second Pool C game next Sunday before a potential pool decider against New Zealand in two weeks' time.
Ireland make fast start
Having failed to qualify for the last World Cup, this Ireland team could not wait to get their tournament up and running and it didn't take them long to make an early impression.
The forwards made a couple of early entries into Japan's 22 but could not penetrate so it fell to the backs to conjure up something creative.
Some slick passing released Costigan out wide to score the opening try in the fifth minute.
When a penalty was kicked to the corner a few minutes later, Ireland's intent was clear and Jones rumbled over for a second try following a line-out maul that took a while to get going.
Having started slowly in the warm-up games against Scotland and Canada, Ireland had talked all week about the pressing need to make a fast start in this game – two tries and a 14-0 lead after 10 minutes meant that box was certainly ticked.
Despite a line-out that was creaking, Ireland's error count was low and they dictated the terms, with O'Brien's kicking game forcing Japan to run out from deep and inevitably get turned over.
Ireland's electric wing Parsons has the capacity to light up this tournament if she gets enough ball.
The first time she got front foot ball in the game, she made it count with Ireland's third try in the 24th minute.
Image source, Inpho
Amee-Leigh Costigan scored Ireland's first try of the tournament
Costigan came across to her wing making the telling pass, and although there was more air on it than Parsons would have liked, she didn't break her stride and pure speed took her over in the corner.
Another great conversion from O'Brien made it 21-0 and everything was going to plan for Ireland.
Japan pulled a try back just before the half hour mark.
Komachi Imakugi was denied out wide by superb tackle by Stacey Flood, but they recycled and Hirotsu bundled over for a deserved try. Otsuka added the extras.
The reaction to Tuite's try summed up the togetherness and spirit that now exists within this Ireland squad.
Eve Higgins made all the running but knew she was about to be caught and wisely passed inside to the support runner Tuite who just had to power through the last few metres to secure a fourth Irish try and the bonus point after 36 minutes.
She raised an arm in celebration to the subs warming up behind that goal and they immediately ran over and surrounded her.
For Ireland, it was a first half that had gone to plan, with O'Brien's conversion putting Ireland 28-7 up at the interval.
Higgins try swings momentum
Japan at times showed great patience and their second try, much like their first, came after they went through a number of phases up front before flanker Kawamura dotted down.
The seven-pointer kept the game interesting and given the one-sided nature of some of the pool games so far, battling Japan at least tried to keep the game in the balance for as long as they could.
They almost scored a third try but a slack pass almost on the Irish line was gobbled up by Higgins who ran almost the entire length of the field unchallenged for try number five for Ireland on 53 minutes.
It was cruel luck on Japan, who looked set to score a third try but instead it was the girls in green who opened up a 35-14 lead.
There were no real complaints from Ireland when a subsequent penalty try was disallowed for obstruction and with a quarter of the game to go, the Ireland coaching staff called for the replacements making five changes, three in the pack and two backs.
One of the replacements, Breen, crashed over for a sixth Irish try soon after with the game getting stretched, bodies getting tired and thoughts inevitably turning towards a second pool game against Spain back here in the Gardens next week.