DeadlySurgeon said: Are Shogi boards normally that big?
This is actually called "dai shogi". It's a variation of the original shogi, only that it has much more different pieces like the elephant and lion, and a bigger board.
The board appears to be 25x25, which would actually make it "tai shogi" ("Grand Shogi"). Dai shogi ("Big Shogi"), which is what Nitori and Momiji are usually depicted as playing, is played on a 15x15 board.
Tai shogi, with its 177 pieces (93 distinct) per side, was believed to be the largest playable chess-like game ever created, until an even larger variant, "taikyouku" or "Ultimate" shogi, was rediscovered in the 1990s. That game is played on a 36x36 board with a staggering 402 pieces (209 distinct) per player. For obvious reasons, neither tai shogi nor taikyouku shogi were ever widely played and both games eventually died off during the 17th century; indeed, a complete set of rules for them have not survived to the present day and most of what we know about how they were played is based on extrapolation. Dai shogi, alone of the "large" shogi variants, remains somewhat popular today.