diff --git a/scanner/scanner.go b/scanner/scanner.go
index 4ef05e3..fb068ed 100644
--- a/scanner/scanner.go
+++ b/scanner/scanner.go
@@ -250,7 +250,17 @@ func (s *Scanner) scanSingleQuote(ctx *Context) (*token.Token, error) {
 				}
 			}
 			continue
-		} else if isFirstLineChar && (c == ' ' || c == '\t') {
+		} else if isFirstLineChar && c == ' ' {
+			continue
+		} else if isFirstLineChar && c == '\t' {
+			if s.lastDelimColumn >= s.column {
+				return nil, ErrInvalidToken(
+					token.Invalid(
+						"tab character cannot be used for indentation in single-quoted text",
+						string(ctx.obuf), s.pos(),
+					),
+				)
+			}
 			continue
 		} else if c != '\'' {
 			value = append(value, c)
@@ -338,7 +348,17 @@ func (s *Scanner) scanDoubleQuote(ctx *Context) (*token.Token, error) {
 				}
 			}
 			continue
-		} else if isFirstLineChar && (c == ' ' || c == '\t') {
+		} else if isFirstLineChar && c == ' ' {
+			continue
+		} else if isFirstLineChar && c == '\t' {
+			if s.lastDelimColumn >= s.column {
+				return nil, ErrInvalidToken(
+					token.Invalid(
+						"tab character cannot be used for indentation in double-quoted text",
+						string(ctx.obuf), s.pos(),
+					),
+				)
+			}
 			continue
 		} else if c == '\\' {
 			isFirstLineChar = false
@@ -1413,6 +1433,12 @@ func (s *Scanner) scan(ctx *Context) error {
 				s.progressColumn(ctx, 1)
 				continue
 			}
+			if s.lastDelimColumn < s.column {
+				s.indentNum++
+				ctx.addOriginBuf(c)
+				s.progressColumn(ctx, 1)
+				continue
+			}
 			if err := s.scanTab(ctx, c); err != nil {
 				return err
 			}
diff --git a/yaml_test_suite_test.go b/yaml_test_suite_test.go
index ca52dbc..becce12 100644
--- a/yaml_test_suite_test.go
+++ b/yaml_test_suite_test.go
@@ -42,10 +42,6 @@ var failureTestNames = []string{
 	"various-trailing-comments-1-3",                    // no json.
 	"zero-indented-sequences-in-explicit-mapping-keys", // no json.
 
-	"legal-tab-after-indentation",                    // pass yamlv3.
-	"multiline-plain-value-with-tabs-on-empty-lines", // pass yamlv3.
-	"tabs-that-look-like-indentation/05",             // pass yamlv3.
-
 	"colon-at-the-beginning-of-adjacent-flow-scalar",
 	"comment-without-whitespace-after-doublequoted-scalar",
 	"construct-binary",
@@ -61,14 +57,8 @@ var failureTestNames = []string{
 	"spec-example-9-3-bare-documents",
 	"spec-example-9-6-stream",
 	"spec-example-9-6-stream-1-3",
-	"tab-at-beginning-of-line-followed-by-a-flow-mapping",
-	"tab-indented-top-flow",
 	"tabs-in-various-contexts/003",
-	"tabs-that-look-like-indentation/00",
-	"tabs-that-look-like-indentation/01",
-	"tabs-that-look-like-indentation/03",
 	"tabs-that-look-like-indentation/04",
-	"tabs-that-look-like-indentation/07",
 	"tag-shorthand-used-in-documents-but-only-defined-in-the-first",
 	"trailing-line-of-spaces/01",             // last '\n' character is needed ?
 	"wrong-indented-flow-sequence",           // error ?