Provided herein is a method of determining a sequence of a target polynucleotide. The method can include the steps of a) providing a device including an array of relatively short polynucleotides and relatively long polynucleotides immobilised on a surface of a solid support, wherein the relatively long polynucleotides are fragments of the target polynucleotide and wherein the relatively long polynucleotides are separated by a distance of at least 10 nm, whereby parts of the relatively long polynucleotides that extend beyond the relatively short polynucleotides can be individually optically resolved; and b) determining the sequence of the target polynucleotide by detecting incorporation of nucleotides into strands complementary to the relatively long polynucleotide fragments using fluorescent labels associated with the incorporated nucleotides. Also provided is system for determining a sequence of a target polynucleotide. The system can include means for carrying out steps a) and b) of the above method.