Cape Town - Springbok coach Rassie Erasmus says his side deliberately played without the ball for large parts against Japan in order to prepare for the All Blacks.

The Boks beat the Japanese 41-7 in Saitama last Friday but their win was based on a staunch defensive effort.

Erasmus' charges only had 36% possession but defended their tryline like Trojans.

But this was the plan, Erasmus admitted, as the South Africans expect dominating possession to be difficult in their opening World Cup game against New Zealand in Yokohama.

"Playing without the ball was intentional. Just for this first game to see how it goes. Because we never know what it (the weather conditions) will be like against New Zealand," Erasmus said, as quoted by the NZ Herald website.

Conditions are expected to be slippery in South Africa's opener against New Zealand - either because of rain or simply wet due to the extreme heat and humidity in Japan.

This makes a possession-dominated game plan tough to execute.

"One of our first priorities was to adapt to the weather circumstances. The humidity meant the ball was wet, after 25 minutes all the jerseys were wet and the arms were wet. We are used to this sort of thing from games in Durban in February so we treated it like it was a wet weather game," Erasmus added.

"It paid off a bit but there were times when Japan almost got away and scored tries. So I would say that there were stages we were really effective in doing it but also Japan could have capitalised on opportunities at other stages and then it could have been a different game."

The Springboks are in Kagoshima this week where more than 6 000 locals watched them train in sweltering heat on Monday.

The Boks were the first of the visiting World Cup teams to touch down in Japan and Erasmus said it was to properly acclimatise to the hot and humid conditions.

The coach also explained why they chose Kagoshima as their base this week: "We visited quite a few sites to see which was the best opportunity for us, and Kagoshima was the best. Everything is top notch, the hotel, the food and the training facility so we’re very happy here and that's given us a good chance to do well in the World Cup.

"We also chose it because the extreme conditions of the heat makes sure the body is well conditioned so that when we get to the match it's easier. It was part of the thinking in planning to put the guys in some extreme conditions so that when it comes to the match they would be well prepared."

The Springboks will transfer to Tokyo on Saturday for the official Rugby World Cup welcoming ceremony.

The Test against the All Blacks in Yokohama is scheduled for September 21.

Compiled by Herman Mostert