The .5 Strategy
The .5 strategy is applied to TH9 to TH11 players – specifically know as TH8.5, TH9.5 and TH10.5. Let’s talk about the basics first.
When your clan decides to go to Clan War the matchmaking algorithm will sum up all your defensive strength and your offensive strength with a metric called war weight.
At a glance, every upgrade & building you have will add a specific war weight. The total war weight is a big part of what matchmaking uses to find similar clans along with similar Town Hall levels.
If you really want to know everything about war weight you should check this recent article I wrote:
This is where the .5 strategy starts. A player decides to go to a new Town Hall level, e.g. TH9, but only upgrades troops. In war weight, the base will be weighted as a TH8 base, but the base has very strong troops and is able to attack all TH9 bases.
This gives an advantage because you will be matched against weaker opponents. You have 2 attacks where you can score 6 Stars in total, while your base can only lose 3 Stars in total.