This study investigates what sentence processing strategies children utilize during their first language (L1) acquisition. Zhai (2012) proposes that when processing empty subject sentences (Chinese)children use cognitive strategies in the early stages of language acquisition, and once they learn or acquire some linguistic knowledge, they start using this knowledge when they comprehend sentences: Developmental Shift of Parsing Strategies. This paper introduces the results of the experiments that tested this hypothesis with Japanese children, and shows that Japanese children also tend to rely on their cognitive abilities while they have not learnt the linguistic knowledge necessary to determine interpretation of the test sentences, and the children in the higher grades use the acquired linguistic knowledge to understand the meaning of the sentences.