According to one embodiment, a shift register memory writes data having a first size corresponding to a capacity of a block to a plurality of layers of a plurality of data storing shift strings included in the block, in response to a first command sequence specifying a first write mode from a controller. In response to a second command sequence specifying a second write mode from the controller, the shift register memory writes data having a second size smaller than the capacity of the block to the plurality of layers of one or more first data storing shift strings of the plurality of data storing shift strings, without writing data to each of other data storing shift strings except the one or more first data storing shift strings.