The Master Deck Build Box EX (Japanese: トッププレイヤーが選ぶ100＋40枚 マスターデッキビルドBOX EXTop Player Choice 100+40 Cards Master Deck Build Box EX) is a special collection of cards released in Japan for the Pokémon Trading Card Game.
The Master Deck Build Box EX contains a selection of cards from the BW era that have been featured in decks used by players that have ranked highly in tournaments. While all cards have been released previously in other expansions, all have a collection number and symbol exclusive to the set. The main focus of the set is to inform players of decks that have performed well, as well as how key cards work within them, and how other cards can be integrated into them as to replicate a competitive deck. The accompanying Master Deck Build Book goes through this in detail. The set also contains a long card box and three partitions to store cards.
Two campaigns also ran in selected stores across Japan in conjunction with the release of the set. Customers who purchased this set between September 14, 2012 and November 26, 2012 were eligible to enter the '100 Pack Win!' campaign, in which the winner received 100 booster packs from a combination of the Dragon Blast/Dragon Blade, Freeze Bolt/Cold Flare, and Plasma Gale expansions. Customers who purchased this set at tournaments held during October and November 2012 were eligible to enter the 'Limited Deck Shield Get!' campaign, in which winners received specially designed card sleeves.