  The Chinese language has evolved a lot during the long-term development.
Therefore, native speakers now have trouble in reading sentences written in
ancient Chinese. In this paper, we propose to build an end-to-end neural model
to automatically translate between ancient and contemporary Chinese. However,
the existing ancient-contemporary Chinese parallel corpora are not aligned at
the sentence level and sentence-aligned corpora are limited, which makes it
difficult to train the model. To build the sentence level parallel training
data for the model, we propose an unsupervised algorithm that constructs
sentence-aligned ancient-contemporary pairs by using the fact that the aligned
sentence pair shares many of the tokens. Based on the aligned corpus, we
propose an end-to-end neural model with copying mechanism and local attention
to translate between ancient and contemporary Chinese. Experiments show that
the proposed unsupervised algorithm achieves 99.4% F1 score for sentence
alignment, and the translation model achieves 26.95 BLEU from ancient to
contemporary, and 36.34 BLEU from contemporary to ancient.
