Korokoro Viking is one of my favourite games in VS Arashi. Many unexpected "accidents" happened during Korokoro Viking. No matter how often Arashi play this game, there's always possibility for them to make mistakes in this game.
I was asking to myself when did they play this game for the first time. Then, I watched many old episodes just find out when that game played for the first time. And the answer is November 3rd, 2011, when they played against Team Hunter.
At first, they don't have minus slot. All slots are positive point, just like the guest team. When they played against Team Charisma Housewives (2012.08.02), they added minus slot (-50) for handicap because the score gap is too big. Since they could do it well even with minus slot, Ohno suggested to continue using minus slot. Wow! Ohno gave a daring suggestion. Such a rare occasion.
They can't maintain good performances in that game. MatsuJun said, that game often became the cause of their lose. So, he asked to change minus slot from -50 to -30. He said it in episode when they played against Yokohama F Marinos (2013.06.13). When Black Mayonnaise came as plus one guest in Januari 17, 2013, one of them said minus 50 is too hard for them who only come as plus one guest once in a while.
I don't know when they start getting minus point (-30) if they lost the ball in the middle of game. I've watched many episodes but I haven't found an episode where they stated that new rule. In VS Arashi 2013.09.12 Jun suggest -10 point penalty if they lost a ball since the score gap is too big. However, that's just special rule for that episode. They mentioned the rule in episode against Team Debikuro (2014.11.20) though. However, they didn't mention it as new rule, so I assume they started using that rule few episodes before. But, I can't find that episode.
*Update: I watched episode 2014.09.04, and Heaven's Voice told Arashi to be careful of the new rule. Maybe they start getting minus point when losing ball since that episode. Then, on episode against Team Library Wars (2015.10.08), they change -30 to -20.
Then, they changed that rule again. They add a new "rule": 10 small balls that will be dropped within 60 seconds after regular balls and golden balls. They introduce this new rule in episode against Team Asai Kikoku (2015.03.05). When I watched 2016s episodes, they still use that rule. I'm not sure if they still use that rule now.
On an episode against Team April Fools (2015.03.12) and against Team Assassination Classroom (2015.03.19) Arashi team don't get minus point when they lost the ball. But on episode against Team Youkoso Wagaya e Arashi got minus point again if they lost the ball. On episode against Team Z Island (2015.05.21) they didn't apply that rule. Not sure if they use that rule again after that episode. Mou wakannai. This is confusing.