An apparatus for video decoding includes processing circuitry. The processing circuitry decodes prediction information of a current block from a coded video bitstream. The prediction information is indicative of an intra block copy mode. The current block is one of a plurality of coding blocks in a coding tree block (CTB) with a right to left coding order being allowed within the CTB. Further, the processing circuitry determines a block vector that points to a reference block in a same picture as the current block and checks that two corner samples of the reference block of the reference block have been reconstructed. In addition, the processing circuitry checks that an additional sample of the reference block has been reconstructed. Then, the processing circuitry reconstructs at least a sample of the current block based on reconstructed samples of the reference block that are retrieved from the reference sample memory.