Related party transactions and balances - Customer deposit (Details) - USD ($)	Jun. 30, 2020	Jun. 30, 2019
Related Party Transaction [Line Items]
Customer deposit from related parties	$ 27,395	$ 29,643
CQ Mingwen
Related Party Transaction [Line Items]
Customer deposit from related parties	$ 27,395	$ 29,643

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration